1
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Scesa PD, Roche SP, West L. Enantioselective Synthesis of (+)-Providencin and Its Unexpected Regioisomer via a Biomimetic Norrish-Yang Cyclization from (-)-Bipinnatin E. Org Lett 2024; 26:1123-1127. [PMID: 38096813 DOI: 10.1021/acs.orglett.3c03604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
A biomimetic semisynthesis of the diterpenoid (+)-providencin (2) and the unexpected novel C14 regioisomer 3 was achieved by photoirradiation of the proposed biosynthetic cembranoid precursor (-)-bipinnatin E (1). The absolute configuration assignments of 1 and 2 by correlation were established by X-ray analysis. A combination of NOESY data and photochemical reaction results revealed that both C2 and C14 positions of the macrocycle (-)-1 are suitable for hydrogen abstraction, thus affording an explanation to the mixture of cyclobutane photoproduct isomers obtained by a Norrish-Yang cyclization. These results also support the proposed biosynthetic hypothesis describing the genuine photochemical transformation of (-)-1 into (+)-2, without refuting that both regioisomer products 2/3 might be artifacts of isolation.
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Affiliation(s)
- Paul D Scesa
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Lyndon West
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
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2
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Richaud AD, Mandal S, Das A, Roche SP. Tunable CH/π Interactions within a Tryptophan Zipper Motif to Stabilize the Fold of Long β-Hairpin Peptides. ACS Chem Biol 2023; 18:2555-2563. [PMID: 37976523 DOI: 10.1021/acschembio.3c00553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
The tryptophan zipper (Trpzip) is an iconic folding motif of β-hairpin peptides capitalizing on two pairs of cross-strand tryptophans, each stabilized by an aromatic-aromatic stacking in an edge-to-face (EtF) geometry. Yet, the origins and the contribution of this EtF packing to the unique Trpzip stability remain poorly understood. To address this question of structure-stability relationship, a library of Trpzip hairpins was developed by incorporating readily accessible nonproteinogenic tryptophans of varying electron densities. We found that each EtF geometry was, in fact, stabilized by an intricate combination of XH/π interactions. By tuning the π-electron density of Trpface rings, CH/π interactions are strengthened to gain additional stability. On the contrary, our DFT calculations support the notion that Trpedge modulations are challenging due to their simultaneous paradoxical engagement as H-bond donors in CH/π and acceptors in NH/π interactions.
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Affiliation(s)
- Alexis D Richaud
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Sourav Mandal
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Pashan, Pune 411008, India
| | - Aloke Das
- Department of Chemistry, Indian Institute of Science Education and Research Pune, Pashan, Pune 411008, India
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
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3
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Moxam J, Naylon S, Richaud AD, Zhao G, Padilla A, Roche SP. Passive Membrane Permeability of Sizable Acyclic β-Hairpin Peptides. ACS Med Chem Lett 2023; 14:278-284. [PMID: 36923919 PMCID: PMC10009788 DOI: 10.1021/acsmedchemlett.2c00486] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/24/2023] [Indexed: 01/28/2023] Open
Abstract
The recent shift toward increasingly larger drug modalities has created a significant demand for novel classes of compounds with high membrane permeability that can inhibit intracellular protein-protein interactions (PPIs). While major advances have been made in the design of cell-permeable helices, stapled β-sheets, and cyclic peptides, the development of large acyclic β-hairpins lags far behind. Therefore, we investigated a series of 26 β-hairpins (MW > 1.6 kDa) belonging to a chemical space far beyond the Lipinski "rule of five" (fbRo5) and showed that, in addition to their innate plasticity, the lipophilicity of these peptides (log D 7.4 ≈ 0 ± 0.7) can be tuned to drastically improve the balance between aqueous solubility and passive membrane permeability.
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Affiliation(s)
- Jillene Moxam
- Department
of Chemistry and Biochemistry, Florida Atlantic
University, Boca Raton, Florida 33431, United States
| | - Sarah Naylon
- Department
of Chemistry and Biochemistry, Florida Atlantic
University, Boca Raton, Florida 33431, United States
| | - Alexis D. Richaud
- Department
of Chemistry and Biochemistry, Florida Atlantic
University, Boca Raton, Florida 33431, United States
| | - Guangkuan Zhao
- Department
of Chemistry and Biochemistry, Florida Atlantic
University, Boca Raton, Florida 33431, United States
| | - Alberto Padilla
- Department
of Natural Science, Keiser University, Fort Lauderdale, Florida 33309, United States
| | - Stéphane P. Roche
- Department
of Chemistry and Biochemistry, Florida Atlantic
University, Boca Raton, Florida 33431, United States
- Center
for Molecular Biology and Biotechnology, Florida Atlantic University, Jupiter, Florida 33458, United States
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4
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Richaud AD, Zaghouani M, Zhao G, Wangpaichitr M, Savaraj N, Roche SP. Exploiting the Innate Plasticity of the Programmed Cell Death-1 (PD1) Receptor to Design Pembrolizumab H3 Loop Mimics. Chembiochem 2022; 23:e202200449. [PMID: 36082509 PMCID: PMC10029098 DOI: 10.1002/cbic.202200449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/07/2022] [Indexed: 11/08/2022]
Abstract
Checkpoint blockade of the immunoreceptor programmed cell death-1 (PD1) with its ligand-1 (PDL1) by monoclonal antibodies such as pembrolizumab provided compelling clinical results in various cancer types, yet the molecular mechanism by which this drug blocks the PD1/PDL1 interface remains unclear. To address this question, we examined the conformational motion of PD1 associated with the binding of pembrolizumab. Our results revealed that the innate plasticity of both C'D and FG loops is crucial to form a deep binding groove (371 Å3 ) across several distant epitopes of PD1. This analysis ultimately provided a rational-design to create pembrolizumab H3 loop mimics [RDYRFDMGFD] into β-hairpin scaffolds. As a result, a 20-residue long β-hairpin peptide 1 e was identified as a first-in-class potent PD1-inhibitor (EC50 of 0.29 μM; Ki of 41 nM).
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Affiliation(s)
- Alexis D Richaud
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Mehdi Zaghouani
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Guangkuan Zhao
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, USA
| | | | - Niramol Savaraj
- Miller School of Medicine, University of Miami, Miami, FL 33458, USA
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, USA
- Center for Molecular Biology and Biotechnology, Florida Atlantic University, Jupiter, FL 33458, USA
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5
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Abstract
Despite their pivotal role in defining antibody affinity and protein function, β-hairpins harboring long noncanonical loops remain synthetically challenging because of the large entropic penalty associated with their conformational folding. Little is known about the contribution and impact of stabilizing motifs on the folding of β-hairpins with loops of variable length and plasticity. Here, we report a design of minimalist β-straps (strap = strand + cap) that offset the entropic cost of long-loop folding. The judicious positioning of noncovalent interactions (hydrophobic cluster and salt-bridge) within the novel 8-mer β-strap design RW(V/H)W···WVWE stabilizes hairpins with up to 10-residue loops of varying degrees of plasticity (Tm up to 52 °C; 88 ± 1% folded at 18 °C). This "hyper" thermostable β-strap outperforms the previous gold-standard technology of β-strand-β-cap (16-mer) and provides a foundation for producing new classes of long hairpins as a viable and practical alternative to macrocyclic peptides.
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Affiliation(s)
- Alexis D Richaud
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Guangkuan Zhao
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Samir Hobloss
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
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6
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Scesa PD, West LM, Roche SP. Role of Macrocyclic Conformational Steering in a Kinetic Route toward Bielschowskysin. J Am Chem Soc 2021; 143:7566-7577. [PMID: 33945689 DOI: 10.1021/jacs.1c03336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Macrocyclic furanobutenolide-derived cembranoids (FBCs) are the biosynthetic precursors to a wide variety of highly congested and oxygenated polycyclic (nor)diterpenes (e.g. plumarellide, verrillin, and bielschowskysin). These architecturally complex metabolites are thought to originate from site-selective oxidation of the macrocycle backbone and a series of intricate transannular reactions. Yet the development of a common biomimetic route has been hampered by a lack of synthetic methods for the pivotal furan dearomatization in a regio- and stereoselective manner. To address these shortcomings, a concise strategy of epoxidation followed by a kinetically controlled furan dearomatization is reported. The surprising switch of facial α:β-discrimination observed in the epoxidation of the most strained E-acerosolide versus E-deoxypukalide and E-bipinnatin J derived macrocycles has been rationalized by the variation of the 3D conformational landscape between macrocyclic scaffolds. A careful conformational analysis of these macrocycles by VT-NMR and NOESY experiments at low temperature was supported by DFT calculations to characterize these equilibrating macrocyclic conformers. The shift in conformational topology associated with a swing of the butenolide ring in E-deoxypukalide is in general agreement with the reversal of β-selectivity observed in the epoxidation. We also describe the downstream functionalization of FBC-macrocycles and how the C-7 epoxide configuration is retentively translated to the C-3 stereogenicity in dearomatized products under kinetic control to secure the requisite 3S,7S,8S configurations for the bielschowskysin synthesis. Unlike previously speculated, our results suggest that the most strained FBC-macrocycles bearing a E-(Δ7,8)-alkene moiety may stand as the true biosynthetic precursors to bielschowskysin and several other polycyclic natural products of this class.
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Affiliation(s)
- Paul D Scesa
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Lyndon M West
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
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7
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Abstract
AbstractNature remarkably employs posttranslational modifications of the 20 canonical α-amino acids to devise a far larger structural, conformational, and functional diversity found in non-proteinogenic amino acids (NPAAs), which ultimately translates into a plethora of complex biological functions. Synthetic chemists are continuously trying to reproduce and even extrapolate the repertoire of NPAA building blocks to build structural diversity into bioactive molecules and materials. The direct asymmetric functionalization of α-imino esters represents one of the most robust and attractive routes to NPAAs. This review summarizes the most prominent examples of bench-stable (ald)imine surrogates exploited for the synthesis of NPAAs, including our most recent results in the nucleophilic substitution of α-haloglycines and other α-haloaminals. A synopsis of kinetic studies, reaction optimizations, and enantioselective catalytic methods is also presented.1 Introduction2 Asymmetric Synthesis of Tertiary α-Substituted NPAAs2.1 From N,O-Acetals (α-Hydroxy/Alkyloxy/Acetoxyglycines)2.2 From α-Amido Sulfones2.3 From α-Haloglycine Esters2.4 From N,O-Bis(Boc) Hydroxyglycine3 Asymmetric Synthesis of Acyclic Quaternary α,α-Disubstituted NPAAs4 Concluding Remarks
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Affiliation(s)
- Stéphane P. Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University
- Center for Molecular Biology and Biotechnology, Florida Atlantic University
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8
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Richaud AD, Roche SP. Structure-Property Relationship Study of N-(Hydroxy)Peptides for the Design of Self-Assembled Parallel β-Sheets. J Org Chem 2020; 85:12329-12342. [PMID: 32881524 DOI: 10.1021/acs.joc.0c01441] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The design of novel and functional biomimetic foldamers remains a major challenge in creating mimics of native protein structures. Herein, we report the stabilization of a remarkably short β-sheet by incorporating N-(hydroxy)glycine (Hyg) residues into the backbone of peptides. These peptide-peptoid hybrids form unique parallel β-sheet structures by self-assembly upon hydrogenation. Our spectroscopic and crystallographic data suggest that the local conformational perturbations induced by N-(hydroxy)amides are outweighed by a network of strong interstrand hydrogen bonds.
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Affiliation(s)
- Alexis D Richaud
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States.,Center for Molecular Biology and Biotechnology, Florida Atlantic University, Jupiter, Florida 33458, United States
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9
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Abstract
A versatile synthetic protocol of aza-Friedel-Crafts alkylation has been developed for the synthesis of quaternary α-amino esters. This operationally simple alkylation proceeds under ambient conditions with high efficiency, regioselectivity, and an exceptionally broad scope of arene nucleophiles. A key feature of this alkylation is the role associated with the silver(I) salt counteranions liberated during the reaction. Taking advantage of a phase-transfer counteranion/Brønsted acid pair mechanism, we also report a catalytic enantioselective example of the reaction.
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Affiliation(s)
- Guangkuan Zhao
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Shyam S Samanta
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Jessica Michieletto
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
- Center for Molecular Biology and Biotechnology, Florida Atlantic University, Jupiter, Florida 33458, United States
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10
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Shearer C, Desaunay O, Zorc S, Richaud AD, Samanta SS, Jeedimalla N, Roche SP. Intercepted-Knoevenagel condensation for the synthesis of unsymmetrical fused-tricyclic 4 H-pyrans. Tetrahedron 2019; 75. [PMID: 31741543 DOI: 10.1016/j.tet.2019.130606] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
4H-Pyrans (4H-Pys) and 1,4-dihydropyridines (1,4-DHPs) are important classes of heterocyclic scaffolds in medicinal chemistry. Herein, an indium(III)-catalyzed one-pot domino reaction for the synthesis of highly functionalized 4H-Pys, and a model of 1,4-DHP is reported. This alternative approach to the challenging Hantzsch 4-component reaction enables the synthesis of fused-tricyclic heterocycles, and the mechanistic studies underline the importance of an intercepted-Knoevenagel adduct to achieve higher chemoselectivity towards these types of unsymmetrical heterocycles.
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Affiliation(s)
- Charles Shearer
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, United States
| | - Oriane Desaunay
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, United States
| | - Stephen Zorc
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, United States
| | - Alexis D Richaud
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, United States
| | - Shyam S Samanta
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, United States
| | - Nagalakshmi Jeedimalla
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, United States
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL 33431, United States
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11
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Samanta SS, Roche SP. Cover Feature: Synthesis and Reactivity of α-Haloglycine Esters: Hyperconjugation in Action (Eur. J. Org. Chem. 39/2019). European J Org Chem 2019. [DOI: 10.1002/ejoc.201901447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Shyam S. Samanta
- Department of Chemistry and Biochemistry; Florida Atlantic University; 33431 FL Boca Raton 777 Glades Road United States
| | - Stéphane P. Roche
- Department of Chemistry and Biochemistry; Florida Atlantic University; 33431 FL Boca Raton 777 Glades Road United States
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12
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Abstract
A general and efficient synthesis of α-haloglycine esters from commercially available feedstock chemicals, in a single step, is reported. The reactivity of these α-haloglycine esters with various nucleophiles was studied as surrogates of α-iminoesters upon activation with hydrogen-bond donor catalysts. DFT calculations on the α-haloglycine structures (X = F, Cl, Br) accompanied by an X-ray characterization of the α-bromoglycine ester support the existence of a "generalized" anomeric effect created by hyperconjugation. This peculiar hyperconjugative effect is proposed to be responsible for the enhanced halogen nucleofugality leading to a facile halogen abstraction by hydrogen-bond donor catalysts. This reactivity was exploited with thiourea catalysts on several catalytic transformations (aza-Friedel-Crafts and Mannich reactions) for the synthesis of several types of non-proteinogenic α-amino esters.
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Affiliation(s)
- Shyam S Samanta
- Department of Chemistry and Biochemistry, Florida Atlantic University, Physical Science Building, 777 Glades Road, Boca Raton, FL, 33431, United States
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Physical Science Building, 777 Glades Road, Boca Raton, FL, 33431, United States
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13
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Abstract
We report a chiral-squaramide-catalyzed enantio- and diastereoselective synthesis of α-allyl amino esters. The optimized protocol provides access to N-carbamoyl-protected amino esters via nucleophilic allylation of readily accessible α-chloro glycinates. A variety of useful α-allyl amino esters were prepared, including crotylated products bearing vicinal stereocenters that are inaccessible through enolate alkylation, with high enantioselectivity (up to 97% ee) and diastereoselectivity (>10:1). The reactions display first-order kinetic dependence on both the α-chloro glycinate and the nucleophile, consistent with rate-limiting C-C bond formation. Computational analysis of the uncatalyzed reaction predicts an energetically inaccessible iminium intermediate, and a lower energy concerted SN2 mechanism.
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Affiliation(s)
- Andrew J Bendelsmith
- Department of Chemistry & Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Seohyun Chris Kim
- Department of Chemistry & Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Masayuki Wasa
- Department of Chemistry & Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Stéphane P Roche
- Department of Chemistry & Biochemistry , Florida Atlantic University , Boca Raton , Florida 33431 , United States
| | - Eric N Jacobsen
- Department of Chemistry & Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
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14
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Abstract
RATIONALE While checkpoint inhibitors have revolutionized the treatment of melanoma, it is not known whether switching from one monoclonal antibody drug to another one would be justified in the case of a treatment failure. Herein, we report a case illustrating a durable response to pembrolizumab after a failure with nivolumab. PATIENT CONCERNS A 76-year-old white male noticed an enlarging papular lesion on his neck. DIAGNOSIS Malignant melanoma. INTERVENTIONS The patient underwent surgery in December 2013 and was found to have a B-Rapidly Accelerated Fibrosarcoma (BRAF) V600E mutated melanoma. Treatment with BRAF and MAPK/Erk kinase (MEK) inhibitors along with radiation was initiated. After 1 year, the disease progressed, and the treatment was switched to the cytotoxic T-lymphocyte antigen 4 (CTLA-4) blocking antibody, ipilimumab. As the tumor did not respond, the treatment was changed to programmed cell death receptor-1 (PD-1) blockers: nivolumab followed by pembrolizumab. Since the initial diagnosis, the tumor response was monitored by computed tomography (CT) scans. Immunohistochemistry (IHC) was also used for the assessment of programmed death ligand 1 PD-L1) expression in the neck, lung, and spleen lesions. OUTCOMES The patient had an initial mixed response to nivolumab, but the disease ultimately progressed as evidenced by new metastases to the spleen, thus the treatment was switched to pembrolizumab. After 46 cycles of treatment, all sites of metastases disappeared, including a substantial shrinkage of the splenic metastasis. To gain understanding about the pharmacological differences between nivolumab and pembrolizumab, the PD-1-ligands interactions and conformational dynamics responsible for the PD-1/PD-L1 checkpoint blockade were investigated. The higher affinity of pembrolizumab might likely arise from a unique and large patch of interactions engaging the C'D loop of PD-1, thus forcing an important motion across the PD-1 immunoreceptor. LESSONS In this case report, we described the tolerance and response of a melanoma patient to a sequence of various agents, including ipilimumab, nivolumab, and pembrolizumab. To the best of our knowledge, this is the first clinical report highlighting differences between PD-1 blockers, as shown by the unexpected and durable response of the tumor to pembrolizumab, after a treatment failure with nivolumab.
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Affiliation(s)
- Tanja Lepir
- Department of Veteran Affairs, Bruce W. Carter VA Medical Center, Miami, FL
| | - Mehdi Zaghouani
- Florida Atlantic University, Department of Chemistry and Biochemistry, Boca Raton, FL
| | - Stéphane P. Roche
- Florida Atlantic University, Department of Chemistry and Biochemistry, Boca Raton, FL
- Center for Molecular Biology and Biotechnology at Florida Atlantic University, Boca Raton, FL
| | - Ying-Ying Li
- Department of Veteran Affairs, Bruce W. Carter VA Medical Center, Miami, FL
| | - Miguel Suarez
- Department of Veteran Affairs, Bruce W. Carter VA Medical Center, Miami, FL
| | - Maria Jose Irias
- Department of Veteran Affairs, Bruce W. Carter VA Medical Center, Miami, FL
| | - Niramol Savaraj
- Department of Veteran Affairs, Bruce W. Carter VA Medical Center, Miami, FL
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15
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Jeedimalla N, Jacquet C, Bahneva D, Youte Tendoung JJ, Roche SP. Synthesis of α-Arylated Cycloalkanones from Congested Trisubstituted Spiro-epoxides: Application of the House–Meinwald Rearrangement for Ring Expansion. J Org Chem 2018; 83:12357-12373. [DOI: 10.1021/acs.joc.8b01448] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nagalakshmi Jeedimalla
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Camille Jacquet
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Diana Bahneva
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Jean-Jacques Youte Tendoung
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Stéphane P. Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
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16
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Scesa P, Wangpaichitr M, Savaraj N, West L, Roche SP. A Kinetic Dearomatization Strategy for an Expedient Biomimetic Route to the Bielschowskysin Skeleton. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201711780] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Paul Scesa
- Department of Chemistry & Biochemistry; Florida Atlantic University; 777 Glades Road Boca Raton FL 33431 USA
| | - Medhi Wangpaichitr
- University of Miami School of Medicine; 1475 NW 12 Ave Miami FL 33136 USA
| | - Niramol Savaraj
- University of Miami School of Medicine; 1475 NW 12 Ave Miami FL 33136 USA
| | - Lyndon West
- Department of Chemistry & Biochemistry; Florida Atlantic University; 777 Glades Road Boca Raton FL 33431 USA
| | - Stéphane P. Roche
- Department of Chemistry & Biochemistry; Florida Atlantic University; 777 Glades Road Boca Raton FL 33431 USA
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17
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Scesa P, Wangpaichitr M, Savaraj N, West L, Roche SP. A Kinetic Dearomatization Strategy for an Expedient Biomimetic Route to the Bielschowskysin Skeleton. Angew Chem Int Ed Engl 2018; 57:1316-1321. [DOI: 10.1002/anie.201711780] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Indexed: 01/14/2023]
Affiliation(s)
- Paul Scesa
- Department of Chemistry & Biochemistry; Florida Atlantic University; 777 Glades Road Boca Raton FL 33431 USA
| | - Medhi Wangpaichitr
- University of Miami School of Medicine; 1475 NW 12 Ave Miami FL 33136 USA
| | - Niramol Savaraj
- University of Miami School of Medicine; 1475 NW 12 Ave Miami FL 33136 USA
| | - Lyndon West
- Department of Chemistry & Biochemistry; Florida Atlantic University; 777 Glades Road Boca Raton FL 33431 USA
| | - Stéphane P. Roche
- Department of Chemistry & Biochemistry; Florida Atlantic University; 777 Glades Road Boca Raton FL 33431 USA
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18
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Abstract
An acetyl chloride-mediated cascade transformation involving a primary carbamate, ethyl glyoxylate, and various types of nucleophiles is reported for the synthesis of orthogonally protected α-amino esters. These reactions proceeded rapidly to afford the pivotal α-chloroglycine intermediate in excellent yields, which can be directly functionalized in situ with various types of nucleophiles. A mild and unique AcOH(cat.)/AcCl system was found to promote an autocatalytic-like condensation and facilitate the multicomponent assembly of non-proteinogenic α-amino esters. To better understand this one-pot transformation and the orchestration of the components' condensations, the investigation of a broader scope of nucleophiles and some kinetic studies are presented. Our findings suggest that the halogenation step toward the formation of α-chloroglycine is the rate-determining step likely proceeding through the formation of N-carbamoyl iminium. Also, the initial kinetic profiling for the nucleophilic substitution supports an SN1-like (SN2C+) mechanism in which nucleophiles add to the iminium-chloride tight ionic pair. These results lead ultimately to the design of a new protocol in which an achiral hydrogen bond donor thiourea catalyst was utilized to enhance the reaction scope and enable silylated nucleophiles to be efficiently exploited to synthesize novel non-proteinogenic α-amino esters.
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Affiliation(s)
- Shyam S Samanta
- Department of Chemistry and Biochemistry, Florida Atlantic University , Boca Raton, Florida 33431, United States
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University , Boca Raton, Florida 33431, United States
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19
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Hall AJ, Roche SP, West LM. Synthesis of Briarane Diterpenoids: Biomimetic Transannular Oxa-6π electrocyclization Induced by a UVA/UVC Photoswitch. Org Lett 2017; 19:576-579. [PMID: 28080074 DOI: 10.1021/acs.orglett.6b03689] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A biomimetic synthesis of briareolate ester B (3) from briareolate ester L (1) via the intermediate briareolate ester G (2) has been achieved through a unique transannular oxa-6π electrocyclization induced by UVA light. UVC irradiation of 3 triggered a rapid retro-6π electrocyclization to establish an unprecedented photochromic switch. In the ground state, reaction of 1 led to the formation of a polycyclic γ-spiroketal γ-lactone 5, architecturally related to the ether-bridged cembranoids of the cladiellin class.
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Affiliation(s)
- Andrew J Hall
- Department of Chemistry and Biochemistry, Florida Atlantic University , Boca Raton, Florida 33431, United States
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University , Boca Raton, Florida 33431, United States
| | - Lyndon M West
- Department of Chemistry and Biochemistry, Florida Atlantic University , Boca Raton, Florida 33431, United States
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20
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Jeedimalla N, Flint M, Smith L, Haces A, Minond D, Roche SP. Multicomponent assembly of 4-aza-podophyllotoxins: A fast entry to highly selective and potent anti-leukemic agents. Eur J Med Chem 2015; 106:167-79. [DOI: 10.1016/j.ejmech.2015.10.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 09/30/2015] [Accepted: 10/06/2015] [Indexed: 11/28/2022]
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21
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Abstract
We report a scalable, one-pot Mannich route to enantioenriched α-amino esters by direct reaction of α-chloroglycine ester as a practical imino ester surrogate. The reaction is promoted by a chiral aminothiourea, which is proposed to operate cooperatively by generating an iminium ion by chloride abstraction and an enolate by deprotonation, followed by highly stereoselective C-C bond formation between both reactive intermediates associated non-covalently within the catalyst framework.
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Affiliation(s)
- Masayuki Wasa
- Department
of Chemistry & Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Richard
Y. Liu
- Department
of Chemistry & Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
| | - Stéphane P. Roche
- Department
of Chemistry & Biochemistry, Florida
Atlantic University, Boca Raton, Florida 33431, United States
| | - Eric N. Jacobsen
- Department
of Chemistry & Chemical Biology, Harvard
University, Cambridge, Massachusetts 02138, United States
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22
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Abstract
α-Arylated, α-amino esters are synthesized in one pot, using an AcOH/AcCl autocatalytic system, which promotes simultaneous dehydration–activation before Friedel–Crafts functionalization.
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Affiliation(s)
- Stéphane P. Roche
- Department of Chemistry and Biochemistry
- Florida Atlantic University
- Boca Raton, USA
| | - Shyam S. Samanta
- Department of Chemistry and Biochemistry
- Florida Atlantic University
- Boca Raton, USA
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23
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Affiliation(s)
- Bret Tréguier
- Department of Chemistry and
Biochemistry, Florida Atlantic University, Physical Science Building, 777 Glades
Road, Boca Raton, Florida 33431, United States
| | - Stéphane P. Roche
- Department of Chemistry and
Biochemistry, Florida Atlantic University, Physical Science Building, 777 Glades
Road, Boca Raton, Florida 33431, United States
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24
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Jeedimalla N, Johns J, Roche SP. Mechanistic investigation and implications of a sacrificial aniline for the tandem cascade synthesis of 4-aza-podophyllotoxin analogues. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.08.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Santagata S, Mendillo ML, Tang YC, Subramanian A, Perley CC, Roche SP, Wong B, Narayan R, Kwon H, Koeva M, Amon A, Golub TR, Porco JA, Whitesell L, Lindquist S. Tight coordination of protein translation and HSF1 activation supports the anabolic malignant state. Science 2013; 341:1238303. [PMID: 23869022 PMCID: PMC3959726 DOI: 10.1126/science.1238303] [Citation(s) in RCA: 212] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ribosome is centrally situated to sense metabolic states, but whether its activity, in turn, coherently rewires transcriptional responses is unknown. Here, through integrated chemical-genetic analyses, we found that a dominant transcriptional effect of blocking protein translation in cancer cells was inactivation of heat shock factor 1 (HSF1), a multifaceted transcriptional regulator of the heat-shock response and many other cellular processes essential for anabolic metabolism, cellular proliferation, and tumorigenesis. These analyses linked translational flux to the regulation of HSF1 transcriptional activity and to the modulation of energy metabolism. Targeting this link with translation initiation inhibitors such as rocaglates deprived cancer cells of their energy and chaperone armamentarium and selectively impaired the proliferation of both malignant and premalignant cells with early-stage oncogenic lesions.
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Affiliation(s)
- Sandro Santagata
- Department of Pathology, Brigham and Women’s Hospital, and Harvard Medical School, Boston, MA, USA
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Marc L. Mendillo
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yun-chi Tang
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Casey C. Perley
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Stéphane P. Roche
- Department of Chemistry, Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, Boston MA, USA
| | - Bang Wong
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Rajiv Narayan
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Hyoungtae Kwon
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Martina Koeva
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Angelika Amon
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Todd R. Golub
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - John A. Porco
- Department of Chemistry, Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, Boston MA, USA
| | - Luke Whitesell
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
| | - Susan Lindquist
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
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26
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Lajkiewicz NJ, Roche SP, Gerard B, Porco JA. Enantioselective photocycloaddition of 3-hydroxyflavones: total syntheses and absolute configuration assignments of (+)-ponapensin and (+)-elliptifoline. J Am Chem Soc 2012; 134:13108-13. [PMID: 22804454 PMCID: PMC3529213 DOI: 10.1021/ja305342f] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have previously reported development of biomimetic, asymmetric [3 + 2] photocycloadditions between 3-hydroxyflavones and cinnamate dipolarophiles to access (-)-rocaglamide and related natural products. Herein, we describe enantioselective syntheses of aglain cycloadducts leading to the first total syntheses and absolute configuration assignments of the aglain natural products (+)-ponapensin and (+)-elliptifoline.
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Affiliation(s)
- Neil J. Lajkiewicz
- Department of Chemistry, Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, MA 02215, United States
| | | | | | - John A. Porco
- Department of Chemistry, Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, MA 02215, United States
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27
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Rodrigo CM, Cencic R, Roche SP, Pelletier J, Porco JA. Synthesis of rocaglamide hydroxamates and related compounds as eukaryotic translation inhibitors: synthetic and biological studies. J Med Chem 2011; 55:558-62. [PMID: 22128783 DOI: 10.1021/jm201263k] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The rocaglates/rocaglamides are a class of natural products known to display potent anticancer activity. One such derivative, silvestrol, has shown activity comparable to taxol in certain settings. Here, we report the synthesis of various rocaglamide analogues and identification of a hydroxamate derivative (-)-9 having activity similar to silvestrol in vitro and ex vivo for inhibition of protein synthesis. We also show that (-)-9 synergizes with doxorubicin in vivo to reduce Eμ-Myc driven lymphomas.
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Affiliation(s)
- Christina M Rodrigo
- Department of Chemistry, Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
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28
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Abstract
Evolution in the field of the total synthesis of natural products has led to exciting developments over the last decade. Numerous chemoselective and enantioselective methodologies have emerged from total syntheses, resulting in efficient access to many important natural product targets. This Review highlights recent developments concerning dearomatization, a powerful strategy for the total synthesis of architecturally complex natural products wherein planar, aromatic scaffolds are converted to three-dimensional molecular architectures.
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Affiliation(s)
- Stéphane P. Roche
- Department of Chemistry, Center for Chemical Methodology and Library Development, Boston University 590 Commonwealth Avenue, Boston, MA 02215 (USA)
| | - John A. Porco
- Department of Chemistry, Center for Chemical Methodology and Library Development, Boston University 590 Commonwealth Avenue, Boston, MA 02215 (USA)
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29
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30
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Roche SP, Cencic R, Pelletier J, Porco JA. Biomimetic photocycloaddition of 3-hydroxyflavones: synthesis and evaluation of rocaglate derivatives as inhibitors of eukaryotic translation. Angew Chem Int Ed Engl 2011; 49:6533-8. [PMID: 20687060 DOI: 10.1002/anie.201003212] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Stéphane P Roche
- Department of Chemistry, Center for Chemical Methodology and Library Development (CMLD-BU), Boston University, 590 Commonwealth Avenue, Boston MA, 02215, USA
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31
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Faure S, Hjelmgaard T, Roche SP, Aitken DJ. Passerini reaction-amine deprotection-acyl migration peptide assembly: efficient formal synthesis of cyclotheonamide C. Org Lett 2010; 11:1167-70. [PMID: 19203293 DOI: 10.1021/ol900048r] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A short, convergent, formal total synthesis of cyclotheonamide C is described. The key linear pentapeptide intermediate is assembled at the same time as the elaboration of the alpha-hydroxyhomoarginine (H-hArg) residue via a three-component Passerini reaction-amine deprotection-O,N-acyl migration strategy.
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Affiliation(s)
- Sophie Faure
- Laboratoire de Synthèse et Etude de Systèmes d'Intérêt Biologique, SEESIB (UMR 6504-CNRS), Université Blaise Pascal-Clermont-Ferrand 2, 24 avenue des Landais, 63177 Aubière Cedex, France.
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32
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Affiliation(s)
- Stéphane P. Roche
- Department of Chemistry, Center for Chemical Methodology and Library Development, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA
| | - David J. Aitken
- Université Paris‐Sud 11, Laboratoire de Synthèse Organique & Méthodologie, ICMMO (CNRS UMR 8182), 15 rue Georges Clemenceau, 91405 Orsay cedex, France, Fax: +33‐1‐69156278
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33
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Roche SP, Teyssot ML, Gautier A. Synthesis of 1,2 diamines under environmentally benign conditions: application for the preparation of imidazolidiniums. Tetrahedron Lett 2010. [DOI: 10.1016/j.tetlet.2009.12.072] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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34
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Roche SP, Faure S, El Blidi L, Aitken DJ. Total Synthesis of Cyclotheonamide C by Use of an α-Keto Cyanophosphorane Methodology for Peptide Assembly. European J Org Chem 2008. [DOI: 10.1002/ejoc.200800591] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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