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Wootton JM, Tam JKF, Unsworth WP. Cascade ring expansion reactions for the synthesis of medium-sized rings and macrocycles. Chem Commun (Camb) 2024; 60:4999-5009. [PMID: 38655659 DOI: 10.1039/d4cc01303d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
This Feature Article discusses recent advances in the development of cascade ring expansion reactions for the synthesis of medium-sized rings and macrocycles. Cascade ring expansion reactions have much potential for use in the synthesis of biologically important medium-sized rings and macrocycles, most notably as they don't require high dilution conditions, which are commonly used in established end-to-end macrocyclisation methods. Operation by cascade ring expansion method can allow large ring products to be accessed via rearrangements that proceed exclusively by normal-sized ring cyclisation steps. Ensuring that there is adequate thermodynamic driving force for ring expansion is a key challenge when designing such methods, especially for the expansion of normal-sized rings into medium-sized rings. This Article is predominantly focused on methods developed in our own laboratory, with selected works by other groups also discussed. Thermodynamic considerations, mechanism, reaction design, route planning and future perspective for this field are all covered.
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Affiliation(s)
- Jack M Wootton
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - Jerry K F Tam
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - William P Unsworth
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
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2
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Yang Z, Arnoux M, Hazelard D, Hughes OR, Nabarro J, Whitwood AC, Fascione MA, Spicer CD, Compain P, Unsworth WP. Expanding the scope of the successive ring expansion strategy for macrocycle and medium-sized ring synthesis: unreactive and reactive lactams. Org Biomol Chem 2024; 22:2985-2991. [PMID: 38526035 DOI: 10.1039/d4ob00285g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
New methods are described that expand the scope of the Successive Ring Expansion (SuRE) with respect to synthetically challenging lactams. A protocol has been developed for use with 'unreactive' lactams, enabling SuRE reactions to be performed on subsrates that fail under previously established conditions. Ring expansion is also demonstarted on 'reactive' lactams derived from iminosugars for the first time. The new SuRE methods were used to prepare a diverse array of medium-sized and macrocyclic lactams and lactones, which were evaluted in an anti-bacterial assay against E. coli BW25113WT.
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Affiliation(s)
- Zhongzhen Yang
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
- Department of Pharmacy, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Marion Arnoux
- Laboratoire d'Innovation Moléculaire et Applications (LIMA), Univ. de Strasbourg, Univ. de Haute-Alsace, CNRS (UMR 7042), Equipe de Synthèse Organique et Molécules Bioactives (SYBIO), ECPM, 25 Rue Becquerel, 67000 Strasbourg, France.
| | - Damien Hazelard
- Laboratoire d'Innovation Moléculaire et Applications (LIMA), Univ. de Strasbourg, Univ. de Haute-Alsace, CNRS (UMR 7042), Equipe de Synthèse Organique et Molécules Bioactives (SYBIO), ECPM, 25 Rue Becquerel, 67000 Strasbourg, France.
| | - Owen R Hughes
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
- York Biomedical Research Institute, University of York, Heslington, YO10 5DD, UK
| | - Joe Nabarro
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
- York Biomedical Research Institute, University of York, Heslington, YO10 5DD, UK
| | - Adrian C Whitwood
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - Martin A Fascione
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
- York Biomedical Research Institute, University of York, Heslington, YO10 5DD, UK
| | - Christopher D Spicer
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
- York Biomedical Research Institute, University of York, Heslington, YO10 5DD, UK
| | - Philippe Compain
- Laboratoire d'Innovation Moléculaire et Applications (LIMA), Univ. de Strasbourg, Univ. de Haute-Alsace, CNRS (UMR 7042), Equipe de Synthèse Organique et Molécules Bioactives (SYBIO), ECPM, 25 Rue Becquerel, 67000 Strasbourg, France.
| | - William P Unsworth
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
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3
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Zalessky I, Wootton JM, Tam JKF, Spurling DE, Glover-Humphreys WC, Donald JR, Orukotan WE, Duff LC, Knapper BJ, Whitwood AC, Tanner TFN, Miah AH, Lynam JM, Unsworth WP. A Modular Strategy for the Synthesis of Macrocycles and Medium-Sized Rings via Cyclization/Ring Expansion Cascade Reactions. J Am Chem Soc 2024; 146:5702-5711. [PMID: 38372651 PMCID: PMC10910531 DOI: 10.1021/jacs.4c00659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/20/2024]
Abstract
Macrocycles and medium-sized rings are important in many scientific fields and technologies but are hard to make using current methods, especially on a large scale. Outlined herein is a strategy by which functionalized macrocycles and medium-sized rings can be prepared using cyclization/ring expansion (CRE) cascade reactions, without resorting to high dilution conditions. CRE cascade reactions are designed to operate exclusively via kinetically favorable 5-7-membered ring cyclization steps; this means that the problems typically associated with classical end-to-end macrocyclization reactions are avoided. A modular synthetic approach has been developed to facilitate the simple assembly of the requisite linear precursors, which can then be converted into an extremely broad range of functionalized macrocycles and medium-sized rings using one of nine CRE protocols.
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Affiliation(s)
- Illya Zalessky
- Department
of Chemistry, University of York, York, YO10 5DD U.K.
| | - Jack M. Wootton
- Department
of Chemistry, University of York, York, YO10 5DD U.K.
| | - Jerry K. F. Tam
- Department
of Chemistry, University of York, York, YO10 5DD U.K.
| | | | | | - James R. Donald
- Department
of Chemistry, University of York, York, YO10 5DD U.K.
| | - Will E. Orukotan
- Department
of Chemistry, University of York, York, YO10 5DD U.K.
| | - Lee C. Duff
- Department
of Chemistry, University of York, York, YO10 5DD U.K.
| | - Ben J. Knapper
- Department
of Chemistry, University of York, York, YO10 5DD U.K.
| | | | | | | | - Jason M. Lynam
- Department
of Chemistry, University of York, York, YO10 5DD U.K.
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4
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Orukotan WE, Palate KY, Pogrányi B, Bobinski P, Epton RG, Duff L, Whitwood AC, Grogan G, Lynam JM, Unsworth WP. Divergent Cascade Ring-Expansion Reactions of Acryloyl Imides. Chemistry 2024; 30:e202303270. [PMID: 37987097 DOI: 10.1002/chem.202303270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/16/2023] [Accepted: 11/21/2023] [Indexed: 11/22/2023]
Abstract
Macrocyclic and medium-sized ring ketones, lactones and lactams can all be made from common acryloyl imide starting materials through divergent, one-pot cascade ring-expansion reactions. Following either conjugate addition with an amine or nitromethane, or osmium(VIII)-catalysed dihydoxylation, rearrangement through a four-atom ring expansion takes place spontaneously to form the ring expanded products. A second ring expansion can also be performed following a second iteration of imide formation and alkene functionalisation/ring expansion. In the dihydroxylation series, three- or four-atom ring expansion can be performed selectively, depending on whether the reaction is under kinetic or thermodynamic control.
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Affiliation(s)
- Will E Orukotan
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | | | - Balázs Pogrányi
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Philipp Bobinski
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Ryan G Epton
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Lee Duff
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | | | - Gideon Grogan
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Jason M Lynam
- Department of Chemistry, University of York, York, YO10 5DD, UK
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5
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Calderón JC, Herrera A, Heinemann FW, Langer J, Linden A, Chelouan A, Grasruck A, Añez R, Clark T, Dorta R. Stereochemical Stability of Planar-Chiral Benzazepine Tricyclics: Inversion Energies of P- and S-Alkene Ligands. J Org Chem 2023; 88:16144-16154. [PMID: 37944159 DOI: 10.1021/acs.joc.3c01447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Inversion barriers ΔG‡ for planar chiral phosphine-alkene and sulfonamide-alkene hybrid ligands based on phenyl-dibenz[b,f]azepine have been determined by density-functional theory calculations. Analysis of the structural and electronic characteristics of the minima and transition states explains the magnitudes of ΔG‡ and the geometrical changes during the inversion process. The steric repulsion caused by bulky substituents attached to the azepine nitrogen atom has a pronounced effect on the ΔG‡ value, explaining, inter alia, the stereochemical stability of the P- and S-alkene ligands when compared to the fluxional parent compound where X = H.
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Affiliation(s)
- Jacqueline C Calderón
- Laboratorio de Química Física y Catálisis Computacional, Centro de Química, Instituto Venezolano de Investigaciones Científicas, Apartado 21827, Caracas, Venezuela
- Computer-Chemie-Centrum, Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstraße. 25, 91052 Erlangen, Germany
| | - Alberto Herrera
- Anorganische und Allgemeine Chemie, Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
| | - Frank W Heinemann
- Anorganische und Allgemeine Chemie, Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
| | - Jens Langer
- Anorganische und Metallorganische Chemie, Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
| | - Anthony Linden
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Ahmed Chelouan
- Anorganische und Allgemeine Chemie, Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
| | - Alexander Grasruck
- Anorganische und Allgemeine Chemie, Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
| | - Rafael Añez
- Laboratorio de Química Física y Catálisis Computacional, Centro de Química, Instituto Venezolano de Investigaciones Científicas, Apartado 21827, Caracas, Venezuela
| | - Timothy Clark
- Computer-Chemie-Centrum, Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstraße. 25, 91052 Erlangen, Germany
| | - Romano Dorta
- Anorganische und Allgemeine Chemie, Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany
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6
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Yang Z, Zalessky I, Epton RG, Whitwood AC, Lynam JM, Unsworth WP. Ring Expansion Strategies for the Synthesis of Medium Sized Ring and Macrocyclic Sulfonamides. Angew Chem Int Ed Engl 2023; 62:e202217178. [PMID: 36716014 DOI: 10.1002/anie.202217178] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/16/2023] [Accepted: 01/30/2023] [Indexed: 01/31/2023]
Abstract
Two new ring expansion strategies are reported for the synthesis of medium sized ring and macrocyclic sulfonamides. Both methods can be performed without using classical protecting groups, with the key ring expansion step initiated by nitro reduction and amine conjugate addition respectively. Each method can be used to make diversely functionalised cyclic sulfonamides in good to excellent yields, in a range of ring sizes. The ring size dependency of the synthetic reactions is in good agreement with the outcomes modelled by Density Functional Theory calculations.
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Affiliation(s)
- Zhongzhen Yang
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Illya Zalessky
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Ryan G Epton
- Department of Chemistry, University of York, York, YO10 5DD, UK
| | | | - Jason M Lynam
- Department of Chemistry, University of York, York, YO10 5DD, UK
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7
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A Lewis Acid-Promoted Michael Addition and Ring-Expansion Cascade for the Construction of Nitrogen-Containing Medium-Sized Rings. Molecules 2023; 28:molecules28041650. [PMID: 36838638 PMCID: PMC9966210 DOI: 10.3390/molecules28041650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/03/2023] [Accepted: 02/04/2023] [Indexed: 02/11/2023] Open
Abstract
A Lewis acid-promoted annulation of azadienes and cyclobutamines was developed. This reaction proceeded through Michael addition and ring-expansion cascade, affording the corresponding nitrogen-containing medium-sized rings with a broad scope in moderate to high yields. The catalytic asymmetric version of this reaction has also been explored using a chiral base.
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8
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Xu H, Ma S. Palladium-Catalyzed [6+2] Double Allene Annulation for Benzazocines Synthesis. Angew Chem Int Ed Engl 2023; 62:e202213676. [PMID: 36372784 DOI: 10.1002/anie.202213676] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/07/2022] [Accepted: 11/11/2022] [Indexed: 11/15/2022]
Abstract
An efficient double allene protocol for the formation of benzazocines has been developed. The reaction constitutes a highly regioselective palladium-catalyzed formal [6+2] annulation of allenyl benzoxazinanones with terminal allenes forming the challenging 8-membered cycles. Decent yields and excellent regioselectivity have been observed under mild conditions with a remarkable Z-stereoselectivity for the exo-cyclic C=C bonds. The synthetic potentials of benzazocine products have been demonstrated.
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Affiliation(s)
- Haibo Xu
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, P. R. China.,University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Shengming Ma
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, P. R. China.,Research Center for Molecular Recognition and Synthesis, Department of Chemistry, Fudan University, 220 Handan Road, Shanghai, 200433, P. R. China
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9
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Wales S, Saunthwal RK, Clayden J. C(sp 3)-Arylation by Conformationally Accelerated Intramolecular Nucleophilic Aromatic Substitution (S NAr). Acc Chem Res 2022; 55:1731-1747. [PMID: 35620846 PMCID: PMC9219115 DOI: 10.1021/acs.accounts.2c00184] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Indexed: 12/13/2022]
Abstract
The asymmetric synthesis of heavily substituted benzylic stereogenic centers, prevalent in natural products, therapeutics, agrochemicals, and catalysts, is an ongoing challenge. In this Account, we outline our contribution to this endeavor, describing our discovery of a series of new reactions that not only have synthetic applicability but also present significant mechanistic intrigue. The story originated from our longstanding interest in the stereochemistry and reactivity of functionalized organolithiums. While investigating the lithiation chemistry of ureas (a "Cinderella" sister of the more established amides and carbamates), we noted an unexpected Truce-Smiles (T-S) rearrangement involving the 1,4-N → C transposition of a urea N'-aryl group to the α-carbanion of an adjacent N-benzyl group. Despite this reaction formally constituting an SNAr substitution, we found it to be remarkably tolerant of the electronic properties of the migrating aryl substituent and the degree of substitution at the carbanion. Moreover, in contrast to classical SNAr reactions, the rearrangement was sufficiently rapid that it took place under conditions compatible with configurational stability in an organolithium intermediate, enabling enantiospecific arylation at benzylic stereogenic centers. Experimental and computational studies confirmed a low kinetic barrier to the aryl migration arising from the strong preference for a trans arrangement of the urea N'-aryl and carbonyl groups, populating a reactive conformer in which spatial proximity was enforced between the carbanion and N'-aryl group, hugely accelerating ipso-substitution.This discovery led us to uncover a whole series of conformationally accelerated intramolecular N → C aryl transfers using different anilide-based functional groups, including a diverse range of urea, carbamate, and thiocarbamate-substituted anions. Products included enantioenriched α-tertiary amines (including α-arylated N-heterocycles) and alcohols, as well as rare α-tertiary thiols. Synthetically challenging diarylated centers with differentiated aryl groups featured heavily in all product sets. The absolute enantiospecificity (retention versus inversion) of the reaction was dependent on the heteroatom α to the lithiation site: the origin of this stereodivergence was probed both experimentally and computationally. Asymmetric variants of the rearrangement were realized by enantioselective deprotonation, and connective strategies were developed in which an intermolecular C-C bond-forming event preceded the anionic rearrangement. Substrates where the N'-nucleofuge (at the aryl ipso position) was tethered to the migrating arene allowed us to use the rearrangement as a ring expansion method to generate 8- to 12-membered medium-ring N-heterocycles from very simple precursors. Stabilized carbon nucleophiles such as alkali metal enolates also readily promoted intramolecular N → C aryl transfer in N'-arylureas, opening up access to biologically relevant hydantoins, and enabling a "chiral memory" approach for the (hetero)arylation of chiral α-amino acids with programmable retention or inversion of configuration. Collectively, our studies of electronically versatile T-S rearrangements in anilide-based systems have culminated in a practical and general strategy for transition metal-free C(sp3)-arylation. More broadly, our results highlight the power of conformational activation to achieve unprecedented reactivity in the construction of challenging C-C bonds.
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Affiliation(s)
| | | | - Jonathan Clayden
- School of Chemistry, University
of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K.
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10
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Unsworth WP, Stephens TC. Strategies for the Synthesis of Heterocyclic Macrocycles and Medium‐Sized Rings. HETEROCYCLES 2022. [DOI: 10.1002/9783527832002.ch3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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11
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Greaney MF, Whalley DM. Recent Advances in the Smiles Rearrangement: New Opportunities for Arylation. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/a-1710-6289] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
AbstractThe Smiles rearrangement has undergone a renaissance in recent years providing new avenues for non-canonical arylation techniques in both the radical and polar regimes. This short review will discuss recent applications of the reaction (from 2017 to late 2021), including its relevance to areas such as heterocycle synthesis and the functionalization of alkenes and alkynes as well as glimpses at new directions for the field.1 Introduction2 Polar Smiles Rearrangements3 Radical Smiles: Alkene and Alkyne Functionalization4 Radical Smiles: Rearrangements via C–X Bond Cleavage5 Radical Smiles: Miscellaneous Rearrangements6 Conclusions
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12
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Palate KY, Yang Z, Whitwood AC, Unsworth WP. Synthesis of medium-ring lactams and macrocyclic peptide mimetics via conjugate addition/ring expansion cascade reactions. RSC Chem Biol 2022; 3:334-340. [PMID: 35359493 PMCID: PMC8905531 DOI: 10.1039/d1cb00245g] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/08/2022] [Indexed: 11/30/2022] Open
Abstract
A novel conjugate addition/ring expansion (CARE) cascade reaction sequence is reported that enables medium-sized ring and macrocyclic bis-lactams to be prepared from primary amines and cyclic imides. The reactions are simple to perform, generally high yielding, and very broad in scope, especially with respect to the primary amine component. CARE reactions can also be performed iteratively, enabling β-peptoid-based macrocyclic peptide mimetics to be ‘grown’ via well controlled, sequential 4-atom ring expansion reactions, with the incorporation of varied functionalised amines during each iteration. A conjugate addition/ring expansion (CARE) cascade reaction sequence is reported that enables medium-sized ring and macrocyclic bis-lactams to be prepared from primary amines and cyclic imides.![]()
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Affiliation(s)
- Kleopas Y Palate
- Department of Chemistry, University of York, Heslington York YO10 5DD UK
| | - Zhongzhen Yang
- Department of Chemistry, University of York, Heslington York YO10 5DD UK
| | - Adrian C Whitwood
- Department of Chemistry, University of York, Heslington York YO10 5DD UK
| | - William P Unsworth
- Department of Chemistry, University of York, Heslington York YO10 5DD UK
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13
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Radical and Ionic Mechanisms in Rearrangements of o-Tolyl Aryl Ethers and Amines Initiated by the Grubbs-Stoltz Reagent, Et 3SiH/KO tBu. Molecules 2021; 26:molecules26226879. [PMID: 34833971 PMCID: PMC8619283 DOI: 10.3390/molecules26226879] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022] Open
Abstract
Rearrangements of o-tolyl aryl ethers, amines, and sulfides with the Grubbs–Stoltz reagent (Et3SiH + KOtBu) were recently announced, in which the ethers were converted to o-hydroxydiarylmethanes, while the (o-tol)(Ar)NH amines were transformed into dihydroacridines. Radical mechanisms were proposed, based on prior evidence for triethylsilyl radicals in this reagent system. A detailed computational investigation of the rearrangements of the aryl tolyl ethers now instead supports an anionic Truce–Smiles rearrangement, where the initial benzyl anion can be formed by either of two pathways: (i) direct deprotonation of the tolyl methyl group under basic conditions or (ii) electron transfer to an initially formed benzyl radical. By contrast, the rearrangements of o-tolyl aryl amines depend on the nature of the amine. Secondary amines undergo deprotonation of the N-H followed by a radical rearrangement, to form dihydroacridines, while tertiary amines form both dihydroacridines and diarylmethanes through radical and/or anionic pathways. Overall, this study highlights the competition between the reactive intermediates formed by the Et3SiH/KOtBu system.
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14
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Qiao J, Liu H, Wang S. Access to Indole-Annulated Medium-Sized Lactams through Protonation/Deuteration-Induced Ring-Opening of Spiroindolines. ACS OMEGA 2021; 6:25049-25061. [PMID: 34604684 PMCID: PMC8482774 DOI: 10.1021/acsomega.1c04261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Indexed: 06/13/2023]
Abstract
A protocol has been developed to access indole-annulated eight- and nine-membered lactams through protonation-induced ring-opening of spiroindolines, which are dearomative Heck products of tetrahydro-β-carbolines or hexahydroazepino[3,4-b]indoles. Brønsted acids and nucleophiles were explored and compared in the transformation. A combination of deuterated hydrochloride and deuterated methanol enables deuterative ring-opening of spiroindolines to afford medium-sized lactam diastereoisomers with a deuterium content ratio around 1:1.
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Affiliation(s)
- Jianhui Qiao
- State
Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of
Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Huili Liu
- State
Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics,
National Center for Magnetic Resonance in Wuhan, Innovation Academy
for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Shaozhong Wang
- State
Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of
Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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15
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de Ceuninck van Capelle LA, Macdonald JM, Hyland CJT. Stereogenic and conformational properties of medium-ring benzo-fused N-heterocycle atropisomers. Org Biomol Chem 2021; 19:7098-7115. [PMID: 34190302 DOI: 10.1039/d1ob00836f] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Medium-ring (7-9-membered) benzo-fused N-heterocycles - a core structure in several important pharmaceuticals - have a diverse range of interesting conformational and stereochemical properties which arise from restricted bond rotation in the non-aromatic ring. The atropisomers of these pharmaceutically relevant N-heterocycles typically exhibit different biological activities, warranting the need to deeply understand the factors controlling the conformation and stereochemistry of the systems. Beginning with a brief introduction to atropisomer classification, this review will detail a number of medium-ring benzo-fused N-heterocycle systems from the recent literature to provide an overview of structural factors which can affect the atropisomeric nature of the systems by altering the overall conformation and rate of stereo-inversion. As well as general factors such as ring-size and sterics, the impact of additional stereocentres in these systems will be addressed. This includes the differences between sulfur, nitrogen and carbon stereocentres, and the consequences of stereocentre placement around the N-heterocycle ring. Further, conformational stabilisation via non-covalent intramolecular bonds will be explored. As such, this review represents a significant resource for aiding in the design, synthesis and study of new and potentially bioactive medium-ring benzo-fused N-heterocycles.
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Affiliation(s)
- Lillian A de Ceuninck van Capelle
- Molecular Horizons Research Institute, School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia.
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16
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Xiao G, Xu S, Xie C, Zi G, Ye W, Zhou Z, Hou G, Zhang Z. Enantioselective Synthesis of Chiral Substituted 2,4-Diketoimidazolidines and 2,5-Diketopiperazines via Asymmetric Hydrogenation. Org Lett 2021; 23:5734-5738. [PMID: 34240880 DOI: 10.1021/acs.orglett.1c01894] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An enantioselective hydrogenation of 5-alkylidene-2,4-diketoimidazolidines (hydantoins) and 3-alkylidene-2,5-ketopiperazines catalyzed by the Rh/f-spiroPhos complex under mild conditions has been developed, which provides an efficient approach to the highly enantioselective synthesis of chiral hydantoins and 2,5-ketopiperazine derivatives with high enantioselectivities up to 99.9% ee.
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Affiliation(s)
- Guiying Xiao
- Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Shuang Xu
- Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Chaochao Xie
- Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Guofu Zi
- Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | | | | | - Guohua Hou
- Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing 100875, China.,Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhanbin Zhang
- Key Laboratory of Radiopharmaceuticals, College of Chemistry, Beijing Normal University, Beijing 100875, China
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17
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Abrams R, Jesani MH, Browning A, Clayden J. Triarylmethanes and their Medium-Ring Analogues by Unactivated Truce-Smiles Rearrangement of Benzanilides. Angew Chem Int Ed Engl 2021; 60:11272-11277. [PMID: 33830592 PMCID: PMC8252078 DOI: 10.1002/anie.202102192] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/01/2021] [Indexed: 12/17/2022]
Abstract
Intramolecular nucleophilic aromatic substitution (Truce–Smiles rearrangement) of the anions of 2‐benzyl benzanilides leads to triarylmethanes in an operationally simple manner. The reaction succeeds even without electronic activation of the ring that plays the role of electrophile in the SNAr reaction, being accelerated instead by the preferred conformation imposed by the tertiary amide tether. The amide substituent of the product may be removed or transformed into alternative functional groups. A ring‐expanding variant (n to n+4) of the reaction provided a route to doubly benzo‐fused medium ring lactams of 10 or 11 members. Hammett analysis returned a ρ value consistent with the operation of a partially concerted reaction mechanism.
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Affiliation(s)
- Roman Abrams
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Mehul H Jesani
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Alex Browning
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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18
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Yang G, Ke Y, Zhao Y. Stereoselective Access to Polyfunctionalized Nine‐Membered Heterocycles by Sequential Gold and Palladium Catalysis. Angew Chem Int Ed Engl 2021; 60:12775-12780. [DOI: 10.1002/anie.202102061] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/28/2021] [Indexed: 11/05/2022]
Affiliation(s)
- Guoqiang Yang
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Ya‐Ming Ke
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Yu Zhao
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
- Joint School of National University of Singapore and Tianjin University International Campus of Tianjin University Binhai New City Fuzhou 350207 China
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19
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Yang G, Ke Y, Zhao Y. Stereoselective Access to Polyfunctionalized Nine‐Membered Heterocycles by Sequential Gold and Palladium Catalysis. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102061] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Guoqiang Yang
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Ya‐Ming Ke
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
| | - Yu Zhao
- Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117543 Republic of Singapore
- Joint School of National University of Singapore and Tianjin University International Campus of Tianjin University Binhai New City Fuzhou 350207 China
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20
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Abrams R, Jesani MH, Browning A, Clayden J. Triarylmethanes and their Medium‐Ring Analogues by Unactivated Truce–Smiles Rearrangement of Benzanilides. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Roman Abrams
- School of Chemistry University of Bristol, Cantock's Close Bristol BS8 1TS UK
| | - Mehul H. Jesani
- School of Chemistry University of Bristol, Cantock's Close Bristol BS8 1TS UK
| | - Alex Browning
- School of Chemistry University of Bristol, Cantock's Close Bristol BS8 1TS UK
| | - Jonathan Clayden
- School of Chemistry University of Bristol, Cantock's Close Bristol BS8 1TS UK
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21
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Qiao J, Zhao W, Liang Y, Yao ZJ, Wang S. Diastereoselective Access to Tetracyclic Eight-Membered Lactams through a Dearomative Heck Reaction and an Alkylative Ring-Opening Driven by Photoexcited Spiroindolines. Chemistry 2021; 27:6308-6314. [PMID: 33506517 DOI: 10.1002/chem.202005369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/25/2021] [Indexed: 11/05/2022]
Abstract
An external-photocatalyst-free, light-driven alkylative ring-opening of stable spiroindolines was developed to construct indolo- and benzoannulated eight-membered lactams. The spiroindolines were prepared from tetrahydro-β-carbolines by a dearomative Heck reaction. Mechanistic experimental studies on the alkylative ring opening suggested that a photoredox pathway was involved, in which the spiroindoline performed as both reagent and photosensitizer. DFT calculations showed that the radical addition toward a cyclic alkene was the key to the diastereoselective formation of tetracyclic medium-sized lactams.
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Affiliation(s)
- Jianhui Qiao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratoryof Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Wenxuan Zhao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratoryof Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Yong Liang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratoryof Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Zhu-Jun Yao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratoryof Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
| | - Shaozhong Wang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratoryof Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, P. R. China
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22
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Wu HH, Fan XZ, Tang Z, Zhang H, Cai LY, Bi XF, Zhao HW. Palladium-Catalyzed Formal (5 + 6) Cycloaddition of Vinylethylene Carbonates with Isatoic Anhydrides for the Synthesis of Medium-Sized N, O-Containing Heterocycles. Org Lett 2021; 23:2802-2806. [PMID: 33739841 DOI: 10.1021/acs.orglett.1c00729] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Under the reaction conditions of Pd(PPh3)4 (2.5 mol %) and PPh3 (10 mol %) in EtOAc at 60 °C, the formal (5 + 6) cycloaddition of vinylethylene carbonates with isatoic anhydrides proceeded smoothly and furnished medium-sized N,O-containing heterocycles in reasonable chemical yields. The chemical structures of the title products were clearly identified by X-ray diffraction analysis.
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Affiliation(s)
- Hui-Hui Wu
- College of Life Science and Bioengineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - Xiao-Zu Fan
- College of Life Science and Bioengineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - Zhe Tang
- College of Life Science and Bioengineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - Heng Zhang
- College of Life Science and Bioengineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - Lu-Yu Cai
- College of Life Science and Bioengineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - Xiao-Fan Bi
- College of Life Science and Bioengineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
| | - Hong-Wu Zhao
- College of Life Science and Bioengineering, Beijing University of Technology, No.100 Pingleyuan, Chaoyang District, Beijing 100124, P. R. China
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23
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Yasui K, Kamitani M, Fujimoto H, Tobisu M. N-Heterocyclic Carbene-Catalyzed Truce-Smiles Rearrangement of N-Arylacrylamides via the Cleavage of Unactivated C(aryl)-N Bonds. Org Lett 2021; 23:1572-1576. [PMID: 33577343 DOI: 10.1021/acs.orglett.0c04281] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report on the N-heterocyclic carbene (NHC)-catalyzed Truce-Smiles rearrangement of aniline derivatives, in which an unactivated C(aryl)-N bond is cleaved, leading to the formation of a new C(aryl)-C bond. The key to the success of this reaction is the utilization of a highly nucleophilic NHC, which enables the formation of a highly nucleophilic ylide intermediate that is generated from an α,β-unsaturated amide.
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Affiliation(s)
- Kosuke Yasui
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Miharu Kamitani
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Hayato Fujimoto
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Mamoru Tobisu
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.,Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
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24
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Zheng H, Wang R, Wang K, Wherritt D, Arman H, Doyle MP. Formal [4 + 4]-, [4 + 3]-, and [4 + 2]-cycloaddition reactions of donor-acceptor cyclobutenes, cyclopropenes and siloxyalkynes induced by Brønsted acid catalysis. Chem Sci 2021; 12:4819-4824. [PMID: 34168758 PMCID: PMC8179600 DOI: 10.1039/d1sc00158b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 02/16/2021] [Indexed: 02/04/2023] Open
Abstract
Brønsted acid catalyzed formal [4 + 4]-, [4 + 3]-, and [4 + 2]-cycloadditions of donor-acceptor cyclobutenes, cyclopropenes, and siloxyalkynes with benzopyrylium ions are reported. [4 + 2]-cyclization/deMayo-type ring-extension cascade processes produce highly functionalized benzocyclooctatrienes, benzocycloheptatrienes, and 2-naphthols in good to excellent yields and selectivities. Moreover, the optical purity of reactant donor-acceptor cyclobutenes is fully retained during the cascade. The 1,3-dicarbonyl product framework of the reaction products provides opportunities for salen-type ligand syntheses and the construction of fused pyrazoles and isoxazoles that reveal a novel rotamer-diastereoisomerism.
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Affiliation(s)
- Haifeng Zheng
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Rui Wang
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Kan Wang
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Daniel Wherritt
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Hadi Arman
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
| | - Michael P Doyle
- Department of Chemistry, The University of Texas at San Antonio One UTSA Circle San Antonio TX 78249 USA
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25
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Palate KY, Epton RG, Whitwood AC, Lynam JM, Unsworth WP. Synthesis of macrocyclic and medium-sized ring thiolactones via the ring expansion of lactams. Org Biomol Chem 2021; 19:1404-1411. [PMID: 33491715 DOI: 10.1039/d0ob02502j] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A side chain insertion method for the ring expansion of lactams into macrocyclic thiolactones is reported, that can also be incorporated into Successive Ring Expansion (SuRE) sequences. The reactions are less thermodynamically favourable than the analogous lactam- and lactone-forming ring expansion processes (with this notion supported by DFT data), but nonetheless, three complementary protecting group strategies have been developed to enable this challenging transformation to be achieved.
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Affiliation(s)
- Kleopas Y Palate
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - Ryan G Epton
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - Adrian C Whitwood
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - Jason M Lynam
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
| | - William P Unsworth
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.
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26
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Zhang X, Lin L, Li J, Duan S, Long Y, Li J. Recent Progress in the Synthesis of Medium-Sized Ring and Macrocyclic Compounds. CHINESE J ORG CHEM 2021. [DOI: 10.6023/cjoc202010026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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27
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Millward MJ, Ellis E, Ward JW, Clayden J. Hydantoin-bridged medium ring scaffolds by migratory insertion of urea-tethered nitrile anions into aromatic C-N bonds. Chem Sci 2020; 12:2091-2096. [PMID: 34163972 PMCID: PMC8179327 DOI: 10.1039/d0sc06188c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 12/11/2020] [Indexed: 01/07/2023] Open
Abstract
Bicyclic or tricyclic nitrogen-containing heterocyclic scaffolds were constructed rapidly by intramolecular nucleophilic aromatic substitution of metallated nitriles tethered by a urea linkage to a series of electronically unactivated heterocyclic precursors. The substitution reaction constitutes a ring expansion, enabled by the conformationally constrained tether between the nitrile and the heterocycle. Attack of the metallated urea leaving group on the nitrile generates a hydantoin that bridges the polycyclic products. X-ray crystallography reveals ring-dependant strain within the hydantoin.
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Affiliation(s)
- Makenzie J Millward
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Emily Ellis
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - John W Ward
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol Cantock's Close Bristol BS8 1TS UK
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28
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Xie C, Yang D, Wang X, Ma C. A Cascade Reaction of Michael Addition and Truce-Smiles Rearrangement to Synthesize Trisubstituted 4-Quinolone Derivatives. J Org Chem 2020; 85:14937-14944. [PMID: 33146531 DOI: 10.1021/acs.joc.0c01662] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A novel transition-metal-free cascade reaction to synthesize 4-quinolone derivatives has been demonstrated. Michael addition and Truce-Smiles rearrangement are included in this protocol, providing a broad scope of 4-quinolones in moderate-to-excellent yields. This work serves as an example of the use of sulfonamides through Truce-Smiles rearrangement to build heterocyclic compounds under mild conditions.
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Affiliation(s)
- Caixia Xie
- School of Chemistry and Chemical Engineering, Shandong University of Technology, Zibo 255049, P. R. China.,School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P. R. China
| | - Di Yang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P. R. China
| | - Xinfeng Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P. R. China
| | - Chen Ma
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, P. R. China
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29
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Uno H, Kawai K, Shiro M, Shibata N. Modular Synthesis of Medium-Sized Fluorinated and Nonfluorinated Heterocyclic Lactones by Sequential CN-Bond-Cleaving Ring Expansion under Pd Catalysis. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03927] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Hiroto Uno
- Department of Nanopharmaceutical Sciences & Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso, Showa-ku, Nagoya 466-8555, Japan
| | - Koki Kawai
- Department of Nanopharmaceutical Sciences & Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso, Showa-ku, Nagoya 466-8555, Japan
| | - Motoo Shiro
- Rigaku Corporation, 3-9-12, Matsubara-cho, Akishima-shi, Tokyo 196-8666, Japan
| | - Norio Shibata
- Department of Nanopharmaceutical Sciences & Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso, Showa-ku, Nagoya 466-8555, Japan
- Institute of Advanced Fluorine-Containing Materials, Zhejiang Normal University, 688 Yingbin Avenue, 321004 Jinhua, China
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30
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Lawer A, Epton RG, Stephens TC, Palate KY, Lodi M, Marotte E, Lamb KJ, Sangha JK, Lynam JM, Unsworth WP. Evaluating the Viability of Successive Ring-Expansions Based on Amino Acid and Hydroxyacid Side-Chain Insertion. Chemistry 2020; 26:12674-12683. [PMID: 32432817 PMCID: PMC7589337 DOI: 10.1002/chem.202002164] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Indexed: 01/20/2023]
Abstract
The outcome of ring-expansion reactions based on amino/hydroxyacid side-chain insertion is strongly dependent on ring size. This manuscript, which builds upon our previous work on Successive Ring Expansion (SuRE) methods, details efforts to better define the scope and limitations of these reactions on lactam and β-ketoester ring systems with respect to ring size and additional functionality. The synthetic results provide clear guidelines as to which substrate classes are more likely to be successful and are supported by computational results, using a density functional theory (DFT) approach. Calculating the relative Gibbs free energies of the three isomeric species that are formed reversibly during ring expansion enables the viability of new synthetic reactions to be correctly predicted in most cases. The new synthetic and computational results are expected to support the design of new lactam- and β-ketoester-based ring-expansion reactions.
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Affiliation(s)
- Aggie Lawer
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
| | - Ryan G. Epton
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
| | | | | | - Mahendar Lodi
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
| | - Emilie Marotte
- ENSICAEN6 Boulevard Maréchal Juin, CS 4505314050Caen Cedex 04France
| | - Katie J. Lamb
- Department of ChemistryUniversity of YorkYorkYO10 5DDUK
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31
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Zhang Z, Qin Z, Chang W, Li J, Fan R, Wu X, Guo R, Xie X, Zhou L. Nickel‐Catalyzed Decarboxylative Cyclization of Isatoic Anhydrides with Carbodiimides: Synthesis of 2,3‐Dihydroquinazolin‐4(1
H
)‐ones. Adv Synth Catal 2020. [DOI: 10.1002/adsc.202000047] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Zhen Zhang
- College of Chemistry and Chemical EngineeringYantai University Yantai 264005, P. R. of People's Republic of China
| | - Ziqiang Qin
- College of Chemistry and Chemical EngineeringYantai University Yantai 264005, P. R. of People's Republic of China
| | - Wenxu Chang
- Department of Applied ChemistryChina Agricultural University Beijing 100193 People's Republic of China
| | - Jiazhu Li
- College of Chemistry and Chemical EngineeringYantai University Yantai 264005, P. R. of People's Republic of China
| | - Ruoqian Fan
- College of Chemistry and Chemical EngineeringYantai University Yantai 264005, P. R. of People's Republic of China
| | - Xing Wu
- College of Chemistry and Chemical EngineeringYantai University Yantai 264005, P. R. of People's Republic of China
| | - Rongrong Guo
- College of Chemistry and Chemical EngineeringYantai University Yantai 264005, P. R. of People's Republic of China
| | - Xiangqi Xie
- College of Chemistry and Chemical EngineeringYantai University Yantai 264005, P. R. of People's Republic of China
| | - Lanxin Zhou
- College of Chemistry and Chemical EngineeringYantai University Yantai 264005, P. R. of People's Republic of China
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32
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Clarke AK, Unsworth WP. A happy medium: the synthesis of medicinally important medium-sized rings via ring expansion. Chem Sci 2020; 11:2876-2881. [PMID: 34122787 PMCID: PMC8152702 DOI: 10.1039/d0sc00568a] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Medium-sized rings have much promise in medicinal chemistry, but are difficult to make using direct cyclisation methods. In this minireview, we highlight the value of ring expansion strategies to address this long-standing synthetic challenge. We have drawn on recent progress (post 2013) to highlight the key reaction design features that enable successful ‘normal-to-medium’ ring expansion for the synthesis of these medicinally important molecular frameworks, that are currently under-represented in compound screening collections and marketed drugs in view of their challenging syntheses. Ring expansion strategies are ideally suited to make synthetically challenging, medium-sized rings with much potential in medicinal chemistry.![]()
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Affiliation(s)
- Aimee K Clarke
- Department of Chemistry, University of York York YO10 5DD UK
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33
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Kurouchi H, Ohwada T. Synthesis of Medium-Ring-Sized Benzolactams by Using Strong Electrophiles and Quantitative Evaluation of Ring-Size Dependency of the Cyclization Reaction Rate. J Org Chem 2020; 85:876-901. [PMID: 31800245 DOI: 10.1021/acs.joc.9b02843] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Benzolactams with medium-sized rings were synthesized via the electrophilic aromatic substitution reaction of carbamoyl cations (R1R2N+═C═O) in good to high yields without dilution. These reactions were utilized to quantitatively examine the extent of retardation of medium-sized ring formation, compared to five- or six-membered ring formation. The order of reaction rates of formation of cyclic benzolactams is six- > five- > seven- > eight- > nine-membered ring at 25 °C. The present reaction provides a route to eight- and nine-membered benzolactams.
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Affiliation(s)
- Hiroaki Kurouchi
- Research Foundation Itsuu Laboratory , C1232, Kanagawa Science Park R&D Building, 3-2-1 Sakado , Takatsu-ku, Kawasaki , Kanagawa 213-0012 , Japan.,Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-0033 , Japan
| | - Tomohiko Ohwada
- Graduate School of Pharmaceutical Sciences , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-0033 , Japan
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34
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Uno H, Imai T, Harada K, Shibata N. Synthesis of Highly Functionalized 12-Membered Trifluoromethyl Heterocycles via a Nondecarboxylative Pd-Catalyzed [6 + 6] Annulation. ACS Catal 2020. [DOI: 10.1021/acscatal.9b05377] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Hiroto Uno
- Department of Nanopharmaceutical Sciences and Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan
| | - Takanori Imai
- Department of Nanopharmaceutical Sciences and Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan
| | - Kyosuke Harada
- Department of Nanopharmaceutical Sciences and Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan
| | - Norio Shibata
- Department of Nanopharmaceutical Sciences and Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555, Japan
- Institute of Advanced Fluorine-Containing Materials, Zhejiang Normal University, 688 Yingbin Avenue, 321004 Jinhua, China
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35
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Xia ZH, Dai L, Gao ZH, Ye S. N-Heterocyclic carbene/photo-cocatalyzed oxidative Smiles rearrangement: synthesis of aryl salicylates from O-aryl salicylaldehydes. Chem Commun (Camb) 2020; 56:1525-1528. [PMID: 31922178 DOI: 10.1039/c9cc09272b] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The N-heterocyclic carbene/photo-cocatalyzed oxidative Smiles rearrangement of O-aryl salicylaldehydes was developed. Both electron-deficient and electron-rich aryls worked well as migrating groups, giving the corresponding aryl salicylates in good yields. This reaction features formation of two new C-O bonds and one C-O bond cleavage via metal-free oxidation of the Breslow intermediate using oxygen as the terminal oxidant and following the Smiles rearrangement under photocatalysis.
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Affiliation(s)
- Zi-Hao Xia
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Molecular Recognition and Function, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
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36
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Whalley DM, Duong HA, Greaney MF. A visible light-mediated, decarboxylative, desulfonylative Smiles rearrangement for general arylethylamine syntheses. Chem Commun (Camb) 2020; 56:11493-11496. [DOI: 10.1039/d0cc05049k] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A decarboxylative, desulfonylative Smiles rearrangement is reported for the synthesis of a wide range of biologically relevant arylethylamines, including fluorinated phenylethylamines, heterocyclic amphetamines and an unnatural amino acid.
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Affiliation(s)
- David M. Whalley
- Institute of Chemical and Engineering Sciences (ICES) Agency for Science, Technology and Research (A*STAR)
- Singapore
- School of Chemistry
- The University of Manchester
- Manchester M13 9PL
| | - Hung A. Duong
- Institute of Chemical and Engineering Sciences (ICES) Agency for Science, Technology and Research (A*STAR)
- Singapore
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37
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Khalifa MM, Philkhana SC, Golden JE. Synthesis of Ring-Fused, N-Substituted 4-Quinolinones Using pKa-Guided, Base-Promoted Annulations with Isatoic Anhydrides: Total Synthesis of Penicinotam. J Org Chem 2019; 85:464-481. [DOI: 10.1021/acs.joc.9b02541] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Muhammad M. Khalifa
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin—Madison, 777 Highland Ave, Madison, Wisconsin 53703, United States
| | - Satish Chandra Philkhana
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin—Madison, 777 Highland Ave, Madison, Wisconsin 53703, United States
| | - Jennifer E. Golden
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin—Madison, 777 Highland Ave, Madison, Wisconsin 53703, United States
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38
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Rohrbach S, Smith AJ, Pang JH, Poole DL, Tuttle T, Chiba S, Murphy JA. Concerted Nucleophilic Aromatic Substitution Reactions. Angew Chem Int Ed Engl 2019; 58:16368-16388. [PMID: 30990931 PMCID: PMC6899550 DOI: 10.1002/anie.201902216] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/11/2019] [Indexed: 12/31/2022]
Abstract
Recent developments in experimental and computational chemistry have identified a rapidly growing class of nucleophilic aromatic substitutions that proceed by concerted (cSN Ar) rather than classical, two-step, SN Ar mechanisms. Whereas traditional SN Ar reactions require substantial activation of the aromatic ring by electron-withdrawing substituents, such activating groups are not mandatory in the concerted pathways.
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Affiliation(s)
- Simon Rohrbach
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
| | - Andrew J. Smith
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
| | - Jia Hao Pang
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological UniversitySingapore637371Singapore
| | - Darren L. Poole
- GlaxoSmithKline Medicines Research CentreGunnels Wood RoadStevenageSG1 2NYUK
| | - Tell Tuttle
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
| | - Shunsuke Chiba
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological UniversitySingapore637371Singapore
| | - John A. Murphy
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetGlasgowG1 1XLUK
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39
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Barlow HL, Rabet PTG, Durie A, Evans T, Greaney MF. Arylation Using Sulfonamides: Phenylacetamide Synthesis through Tandem Acylation–Smiles Rearrangement. Org Lett 2019; 21:9033-9035. [PMID: 31674791 DOI: 10.1021/acs.orglett.9b03429] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Helen L. Barlow
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Pauline T. G. Rabet
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Alastair Durie
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Tim Evans
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Michael F. Greaney
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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40
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Lawer A, Rossi‐Ashton JA, Stephens TC, Challis BJ, Epton RG, Lynam JM, Unsworth WP. Internal Nucleophilic Catalyst Mediated Cyclisation/Ring Expansion Cascades for the Synthesis of Medium‐Sized Lactones and Lactams. Angew Chem Int Ed Engl 2019; 58:13942-13947. [DOI: 10.1002/anie.201907206] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/23/2019] [Indexed: 12/12/2022]
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41
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Rohrbach S, Smith AJ, Pang JH, Poole DL, Tuttle T, Chiba S, Murphy JA. Konzertierte nukleophile aromatische Substitutionen. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902216] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Simon Rohrbach
- Department of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL Großbritannien
| | - Andrew J. Smith
- Department of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL Großbritannien
| | - Jia Hao Pang
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapur
| | - Darren L. Poole
- GlaxoSmithKline Medicines Research Centre Gunnels Wood Road Stevenage SG1 2NY Großbritannien
| | - Tell Tuttle
- Department of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL Großbritannien
| | - Shunsuke Chiba
- Division of Chemistry and Biological ChemistrySchool of Physical and Mathematical SciencesNanyang Technological University Singapore 637371 Singapur
| | - John A. Murphy
- Department of Pure and Applied ChemistryUniversity of Strathclyde 295 Cathedral Street Glasgow G1 1XL Großbritannien
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42
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Lawer A, Rossi‐Ashton JA, Stephens TC, Challis BJ, Epton RG, Lynam JM, Unsworth WP. Internal Nucleophilic Catalyst Mediated Cyclisation/Ring Expansion Cascades for the Synthesis of Medium‐Sized Lactones and Lactams. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907206] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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43
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Wu A, Feng Q, Sung HHY, Williams ID, Sun J. Synthesis of Eight‐Membered Lactams through Formal [6+2] Cyclization of Siloxy Alkynes and Vinylazetidines. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902866] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- An Wu
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon, Hong Kong SAR China
| | - Qiang Feng
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon, Hong Kong SAR China
| | - Herman H. Y. Sung
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon, Hong Kong SAR China
| | - Ian D. Williams
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon, Hong Kong SAR China
| | - Jianwei Sun
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon, Hong Kong SAR China
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44
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Wu A, Feng Q, Sung HHY, Williams ID, Sun J. Synthesis of Eight-Membered Lactams through Formal [6+2] Cyclization of Siloxy Alkynes and Vinylazetidines. Angew Chem Int Ed Engl 2019; 58:6776-6780. [PMID: 30888103 DOI: 10.1002/anie.201902866] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Indexed: 12/31/2022]
Abstract
A new approach for the efficient synthesis of eight-membered lactams through formal [6+2] cyclization of siloxy alkynes and vinylazetidines has been developed. Evidence from a chirality transfer experiment suggests that the reaction proceeds via a [3,3]-sigmatropic rearrangement from a ketene intermediate. This insight led to the development of alternative conditions and use of acyl chlorides as ketene precursors for the [6+2] reaction with vinylazetidines.
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Affiliation(s)
- An Wu
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Qiang Feng
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Herman H Y Sung
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Ian D Williams
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Jianwei Sun
- Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
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45
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Saini KM, Saunthwal RK, Kumar S, Verma AK. On water: iodine-mediated direct construction of 1,3-benzothiazines from ortho-alkynylanilines by regioselective 6-exo-dig cyclization. Org Biomol Chem 2019; 17:2657-2662. [PMID: 30762860 DOI: 10.1039/c9ob00128j] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Herein, we report the 6-exo-dig ring closure of ortho-alkynylanilines with readily available aroyl isothiocyanate. An environmentally benign, metal- and base-free, iodine promoted cascade synthesis of highly functionalized (benzo[1,3]thiazin-2-yl)benzimidic acids has been accomplished via in situ generated ortho-alkynylthiourea. The established methodology employs the abundant chemical feedstock of ortho-alkynylanilines and aroyl isothiocyanates and could be applied in the late-stage synthesis of pharmaceutically active 1,3-benzothiazine containing molecules. Furthermore, the discovered protocol exclusively delivers bis (benzo[1,3]thiazin-2-yl)dibenzimidic acid products and preserves the iodo-olefin substitution pattern which can be exploited by further derivatization.
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Affiliation(s)
- Kapil Mohan Saini
- Synthetic Organic Chemistry Research Laboratory, Department of Chemistry, University of Delhi, Delhi-110007, India.
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46
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Li C, Wang CS, Li TZ, Mei GJ, Shi F. Brønsted Acid-Catalyzed (4 + 3) Cyclization of N, N'-Cyclic Azomethine Imines with Isatoic Anhydrides. Org Lett 2019; 21:598-602. [PMID: 30645136 DOI: 10.1021/acs.orglett.8b03604] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A Brønsted acid-catalyzed (4 + 3) cyclization of N, N'-cyclic azomethine imines with isatoic anhydrides has been discovered, which constructs seven-membered nitrogenous heterocyclic frameworks with overall high yields (up to 98% yield). This reaction represents a rarely reported (4 + 3) cyclization of N, N'-cyclic azomethine imines, which involves the reassembly of a C-N bond. In addition, this reaction has also accomplished the unprecedented (4 + 3) cyclization of isatoic anhydrides.
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Affiliation(s)
- Can Li
- School of Chemistry and Materials Science , Jiangsu Normal University , Xuzhou 221116 , China
| | - Cong-Shuai Wang
- School of Chemistry and Materials Science , Jiangsu Normal University , Xuzhou 221116 , China
| | - Tian-Zhen Li
- School of Chemistry and Materials Science , Jiangsu Normal University , Xuzhou 221116 , China
| | - Guang-Jian Mei
- School of Chemistry and Materials Science , Jiangsu Normal University , Xuzhou 221116 , China
| | - Feng Shi
- School of Chemistry and Materials Science , Jiangsu Normal University , Xuzhou 221116 , China
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47
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Nikitin K, O'Gara R. Mechanisms and Beyond: Elucidation of Fluxional Dynamics by Exchange NMR Spectroscopy. Chemistry 2019; 25:4551-4589. [PMID: 30421834 DOI: 10.1002/chem.201804123] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Indexed: 12/31/2022]
Abstract
Detailed mechanistic information is crucial to our understanding of reaction pathways and selectivity. Dynamic exchange NMR techniques, in particular 2D exchange spectroscopy (EXSY) and its modifications, provide indispensable intricate information on the mechanisms of organic and inorganic reactions and other phenomena, for example, the dynamics of interfacial processes. In this Review, key results from exchange NMR studies of small molecules over the last few decades are systemised and discussed. After a brief introduction to the theory, the key types of dynamic processes are identified and fundamental examples given of intra- and intermolecular reactions, which, in turn, could involve, or not, bond-making and bond-breaking events. Following that logic, internal molecular rotation, intramolecular stereomutation and molecular recognition will first be considered because they do not typically involve bond breaking. Then, rearrangements, substitution-type reactions, cyclisations, additions and other processes affecting chemical bonds will be discussed. Finally, interfacial molecular dynamics and unexpected combinations of different types of fluxional processes will also be highlighted. How exchange NMR spectroscopy helps to identify conformational changes, coordination and molecular recognition processes as well as quantify reaction energy barriers and extract detailed mechanistic information by using reaction rate theory in conjunction with computational techniques will be shown.
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Affiliation(s)
- Kirill Nikitin
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Ryan O'Gara
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
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48
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Grintsevich S, Sapegin A, Reutskaya E, Krasavin M. Antiviral drug nevirapine as a template for hydrated imidazoline ring expansion (HIRE): Rapid access to the diarene-fused 1,4,7-triazecine ring system. Tetrahedron Lett 2019. [DOI: 10.1016/j.tetlet.2018.11.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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49
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Liu Z, Hu X. Palladium‐Catalyzed Propargylic [n+2] Cycloaddition: An Efficient Strategy for Construction of Benzo‐Fused Medium‐Sized Heterocycles. Adv Synth Catal 2018. [DOI: 10.1002/adsc.201801359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Zhen‐Ting Liu
- Dalian Institute of Chemical PhysicsChinese Academy of Sciences 457 Zhongshan Road Dalian 116023 People's Republic of China
- University of Chinese Academy of Sciences Beijing 100049 People's Republic of China
| | - Xiang‐Ping Hu
- Dalian Institute of Chemical PhysicsChinese Academy of Sciences 457 Zhongshan Road Dalian 116023 People's Republic of China
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50
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Zhou Y, Wei YL, Rodriguez J, Coquerel Y. Enantioselective Organocatalytic Four-Atom Ring Expansion of Cyclobutanones: Synthesis of Benzazocinones. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201810184] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Yirong Zhou
- Aix Marseille Université; CNRS; Centrale Marseille, ISM2; 13397 Marseille France
- Key Laboratory of Functional Small Organic Molecules Ministry of Education; Jiangxi Normal University; 330022 Nanchang China
| | - Yun-Long Wei
- Aix Marseille Université; CNRS; Centrale Marseille, ISM2; 13397 Marseille France
| | - Jean Rodriguez
- Aix Marseille Université; CNRS; Centrale Marseille, ISM2; 13397 Marseille France
| | - Yoann Coquerel
- Aix Marseille Université; CNRS; Centrale Marseille, ISM2; 13397 Marseille France
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