1
|
Gui X, Sorbelli D, Caló FP, Leutzsch M, Patzer M, Fürstner A, Bistoni G, Auer AA. Elucidating the Electronic Nature of Rh-based Paddlewheel Catalysts from 103 Rh NMR Chemical Shifts: Insights from Quantum Mechanical Calculations. Chemistry 2024; 30:e202301846. [PMID: 37721802 DOI: 10.1002/chem.202301846] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 09/18/2023] [Accepted: 09/18/2023] [Indexed: 09/20/2023]
Abstract
The tremendous importance of dirhodium paddlewheel complexes for asymmetric catalysis is largely the result of an empirical optimization of the chiral ligand sphere about the bimetallic core. It was only recently that a H(C)Rh triple resonance 103 Rh NMR experiment provided the long-awaited opportunity to examine - with previously inconceivable accuracy - how variation of the ligands impacts on the electronic structure of such catalysts. The recorded effects are dramatic: formal replacement of only one out of eight O-atoms surrounding the metal centers in a dirhodium tetracarboxylate by an N-atom results in a shielding of the corresponding Rh-site of no less than 1000 ppm. The current paper provides the theoretical framework that allows this and related experimental observations made with a set of 19 representative rhodium complexes to be interpreted. In line with symmetry considerations, it is shown that the shielding tensor responds only to the donor ability of the equatorial ligands along the perpendicular principal axis. Axial ligands, in contrast, have no direct effect on shielding but may come into play via the electronicc i s ${cis}$ -effect that they exert onto the neighboring equatorial sites. On top of these fundamental interactions, charge redistribution within the core as well as the electronict r a n s ${trans}$ -effect of ligands of different donor strengths is reflected in the recorded 103 Rh NMR shifts.
Collapse
Affiliation(s)
- Xin Gui
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Diego Sorbelli
- Dipartmento di Chimica, Biologia e Biotechnologie, Università Degli Studi Di Perugia, 06123, Perugia, Italy
| | - Fabio P Caló
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Michael Patzer
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| | - Giovanni Bistoni
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
- Dipartmento di Chimica, Biologia e Biotechnologie, Università Degli Studi Di Perugia, 06123, Perugia, Italy
| | - Alexander A Auer
- Max-Planck-Institut für Kohlenforschung, 45470, Mülheim an der RuhrMülheim/Ruhr, Germany
| |
Collapse
|
2
|
Harbor-Collins H, Sabba M, Bengs C, Moustafa G, Leutzsch M, Levitt MH. NMR spectroscopy of a 18O-labeled rhodium paddlewheel complex: Isotope shifts, 103Rh-103Rh spin-spin coupling, and 103Rh singlet NMR. J Chem Phys 2024; 160:014305. [PMID: 38174793 DOI: 10.1063/5.0182233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 12/10/2023] [Indexed: 01/05/2024] Open
Abstract
Despite the importance of rhodium complexes in catalysis, and the favorable 100% natural abundance of the spin-1/2 103Rh nucleus, there are few reports of 103Rh nuclear magnetic resonance (NMR) parameters in the literature. In part, this is the consequence of the very low gyromagnetic ratio of 103Rh and its dismal NMR sensitivity. In a previous paper [Harbor-Collins et al., J. Chem. Phys. 159, 104 307 (2023)], we demonstrated an NMR methodology for 1H-enhanced 103Rh NMR and demonstrated an application to the 103Rh NMR of the dirhodium formate paddlewheel complex. In this paper, we employ selective 18O labeling to break the magnetic equivalence of the 103Rh spin pair of dirhodium formate. This allows the estimation of the 103Rh-103Rh spin-spin coupling and provides access to the 103Rh singlet state. We present the first measurement of a 18O-induced 103Rh secondary isotope shift as well as the first instance of singlet order generated in a 103Rh spin pair. The field-dependence of 103Rh singlet relaxation is measured by field-cycling NMR experiments.
Collapse
Affiliation(s)
- Harry Harbor-Collins
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Mohamed Sabba
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Christian Bengs
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Gamal Moustafa
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr 45470, Germany
| | - Malcolm H Levitt
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| |
Collapse
|
3
|
Sailer J, Sharland JC, Bacsa J, Harris CF, Berry JF, Musaev DG, Davies HML. Diruthenium Tetracarboxylate-Catalyzed Enantioselective Cyclopropanation with Aryldiazoacetates. Organometallics 2023; 42:2122-2133. [PMID: 37592951 PMCID: PMC10428512 DOI: 10.1021/acs.organomet.3c00268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Indexed: 08/19/2023]
Abstract
A series of chiral bowl-shaped diruthenium(II,III) tetracarboxylate catalysts were prepared and evaluated in asymmetric cyclopropanations with donor/acceptor carbenes derived from aryldiazoacetates. The diruthenium catalysts self-assembled to generate C4-symmetric bowl-shaped structures in an analogous manner to their dirhodium counterparts. The optimum catalyst was found to be Ru2(S-TPPTTL)4·BArF [S-TPPTTL = (S)-2-(1,3-dioxo-4,5,6,7-tetraphenylisoindolin-2-yl)-3,3-dimethylbutanoate, BArF = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate], which resulted in the cyclopropanation of a range of substrates in up to 94% ee. Synthesis and evaluation of first-row transition-metal congeners [Cu(II/II) and Co(II/II)] invariably resulted in catalysts that afforded little to no asymmetric induction. Computational studies indicate that the carbene complexes of these dicopper and dicobalt complexes, unlike the dirhodium and diruthenium systems, are prone to the loss of carboxylate ligands, which would destroy the bowl-shaped structure critical for asymmetric induction.
Collapse
Affiliation(s)
- Joshua
K. Sailer
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Jack C. Sharland
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - John Bacsa
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Caleb F. Harris
- Department
of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - John F. Berry
- Department
of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Djamaladdin G. Musaev
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
- Cherry
L. Emerson Center for Scientific Computation, Emory University, 1521
Dickey Drive, Atlanta, Georgia 30322, United States
| | - Huw M. L. Davies
- Department
of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| |
Collapse
|
4
|
Caló FP, Zimmer A, Bistoni G, Fürstner A. From Serendipity to Rational Design: Heteroleptic Dirhodium Amidate Complexes for Diastereodivergent Asymmetric Cyclopropanation. J Am Chem Soc 2022; 144:7465-7478. [PMID: 35420801 PMCID: PMC9052758 DOI: 10.1021/jacs.2c02258] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
![]()
A heteroleptic dirhodium
paddlewheel complex comprising three chiral
carboxylate ligands and one achiral acetamidate ligand has recently
been found to be uniquely effective in catalyzing the asymmetric cyclopropanation
of olefins with α-stannylated (silylated and germylated) α-diazoacetate
derivatives. A number of control experiments in combination with detailed
computational studies provide compelling evidence that an interligand
hydrogen bond between the −NH group of the amidate and the
ester carbonyl group of the reactive rhodium carbene intermediate
plays a quintessential role in the stereodetermining transition state.
The penalty for distorting this array outweighs steric arguments and
renders two of the four conceivable transitions states unviable. Based
on this mechanistic insight, the design of the parent catalyst is
revisited herein: placement of appropriate peripheral substituents
allows high levels of diastereocontrol to be imposed upon cyclopropanation,
which the original catalyst lacks. Because the new complexes allow
either trans- or cis-configured stannylated cyclopropanes to be made
selectively and in excellent optical purity, this transformation also
marks a rare case of diastereodivergent asymmetric catalysis. The
products are amenable to stereospecific cross coupling with aryl halides
or alkenyl triflates; these transformations appear to be the first
examples of the formation of stereogenic quaternary carbon centers
by the Stille reaction; carbonylative coupling is also achieved. Moreover,
tin/lithium exchange affords chiral lithium enolates, which can be
intercepted with a variety of electrophilic partners. The virtues
and inherent flexibility of this new methodology are illustrated by
an efficient synthesis of two salinilactones, extremely scarce bacterial
metabolites with signaling function involved in the self-regulatory
growth inhibition of the producing strain.
Collapse
Affiliation(s)
| | - Anne Zimmer
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
| | - Giovanni Bistoni
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung, Mülheim/Ruhr D-45470, Germany
| |
Collapse
|
5
|
Laconsay CJ, Pla-Quintana A, Tantillo DJ. Effects of Axial Solvent Coordination to Dirhodium Complexes on the Reactivity and Selectivity in C–H Insertion Reactions: A Computational Study. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00574] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Croix J. Laconsay
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Anna Pla-Quintana
- Department of Chemistry, University of California, Davis, California 95616, United States
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Facultat de Ciències, Universitat de Girona (UdG), C/Maria Aurèlia Capmany, 69, Girona 17003, Catalunya, Spain
| | - Dean J. Tantillo
- Department of Chemistry, University of California, Davis, California 95616, United States
| |
Collapse
|