1
|
Taufa T, Gordon RM, Hashmi MA, Hira K, Miller JH, Lein M, Fromont J, Northcote PT, Keyzers RA. Pyrroloquinoline derivatives from a Tongan specimen of the marine sponge Strongylodesma tongaensis. Tetrahedron Lett 2019. [DOI: 10.1016/j.tetlet.2019.06.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
2
|
Carden RG, Lam N, Widenhoefer RA. Experimental Evaluation of (L)Au Electron‐Donor Ability in Cationic Gold Carbene Complexes. Chemistry 2017; 23:17992-18001. [DOI: 10.1002/chem.201703820] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Robert G. Carden
- Department of Chemistry Duke University French Family Science Center Durham North Carolina USA
| | - Nathan Lam
- Department of Chemistry Duke University French Family Science Center Durham North Carolina USA
| | - Ross A. Widenhoefer
- Department of Chemistry Duke University French Family Science Center Durham North Carolina USA
| |
Collapse
|
3
|
West TH, Walden DM, Taylor JE, Brueckner AC, Johnston RC, Cheong PHY, Lloyd-Jones GC, Smith AD. Catalytic Enantioselective [2,3]-Rearrangements of Allylic Ammonium Ylides: A Mechanistic and Computational Study. J Am Chem Soc 2017; 139:4366-4375. [PMID: 28230365 PMCID: PMC5374492 DOI: 10.1021/jacs.6b11851] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A mechanistic study of the isothiourea-catalyzed enantioselective [2,3]-rearrangement of allylic ammonium ylides is described. Reaction kinetic analyses using 19F NMR and density functional theory computations have elucidated a reaction profile and allowed identification of the catalyst resting state and turnover-rate limiting step. A catalytically relevant catalyst-substrate adduct has been observed, and its constitution elucidated unambiguously by 13C and 15N isotopic labeling. Isotopic entrainment has shown the observed catalyst-substrate adduct to be a genuine intermediate on the productive cycle toward catalysis. The influence of HOBt as an additive upon the reaction, catalyst resting state, and turnover-rate limiting step has been examined. Crossover experiments have probed the reversibility of each of the proposed steps of the catalytic cycle. Computations were also used to elucidate the origins of stereocontrol, with a 1,5-S···O interaction and the catalyst stereodirecting group providing transition structure rigidification and enantioselectivity, while preference for cation-π interactions over C-H···π is responsible for diastereoselectivity.
Collapse
Affiliation(s)
- Thomas H West
- EaStCHEM, School of Chemistry, University of St Andrews , North Haugh, St. Andrews, KY16 9ST, U.K
| | - Daniel M Walden
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97333, United States
| | - James E Taylor
- EaStCHEM, School of Chemistry, University of St Andrews , North Haugh, St. Andrews, KY16 9ST, U.K
| | - Alexander C Brueckner
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97333, United States
| | - Ryne C Johnston
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97333, United States
| | - Paul Ha-Yeon Cheong
- Department of Chemistry, Oregon State University , 153 Gilbert Hall, Corvallis, Oregon 97333, United States
| | - Guy C Lloyd-Jones
- EaStCHEM, School of Chemistry, University of Edinburgh , Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, U.K
| | - Andrew D Smith
- EaStCHEM, School of Chemistry, University of St Andrews , North Haugh, St. Andrews, KY16 9ST, U.K
| |
Collapse
|
4
|
Bender CF, Brown TJ, Widenhoefer RA. Mechanism of the Platinum(II)-Catalyzed Hydroamination of 4-Pentenylamines. Organometallics 2016. [DOI: 10.1021/acs.organomet.5b00821] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher F. Bender
- Department of Chemistry,
French Family Science Center, Duke University, Durham, North Carolina 27708-0346, United States
| | - Timothy J. Brown
- Department of Chemistry,
French Family Science Center, Duke University, Durham, North Carolina 27708-0346, United States
| | - Ross A. Widenhoefer
- Department of Chemistry,
French Family Science Center, Duke University, Durham, North Carolina 27708-0346, United States
| |
Collapse
|
5
|
Denisov AY, Mamatyuk VI, Shkurko OP. 13C-13C spin-spin coupling constants in the spectra of monosubstituted pyridines. Chem Heterocycl Compd (N Y) 1985. [DOI: 10.1007/bf00515254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|