A Selenourea-Thiourea Brønsted Acid Catalyst Facilitates Asymmetric Conjugate Additions of Amines to α,β-Unsaturated Esters
作者:Yingfu Lin、William J. Hirschi、Anuj Kunadia、Anirudra Paul、Ion Ghiviriga、Khalil A. Abboud、Rachael W. Karugu、Mathew J. Vetticatt、Jennifer S. Hirschi、Daniel Seidel
DOI:10.1021/jacs.9b12457
日期:2020.3.25
enantioselectivity via the conjugate addition of cyclic amines to unactivated α,β-unsaturated esters. A related strategy enables the kineticresolution of racemic cyclic 2-arylamines, using benzyl acrylate as the resolving agent. Reactions are facilitated by an unprecedented selenourea-thiourea organocatalyst. As elucidated by DFT calculations and 13C kinetic isotope effects studies, the rate-limiting and enantiodetermining
Asymmetric Substitutions of 2-Lithiated N-Boc-piperidine and N-Boc-azepine by Dynamic Resolution
作者:Iain Coldham、Sophie Raimbault、David T. E. Whittaker、Praful T. Chovatia、Daniele Leonori、Jignesh J. Patel、Nadeem S. Sheikh
DOI:10.1002/chem.200903059
日期:2010.4.6
(N‐Boc‐piperidine) with sBuLi and TMEDA provides a racemic organolithium that can be resolved using a chiral ligand. The enantiomeric organolithiums can interconvert so that a dynamic resolution occurs. Two mechanisms for promoting enantioselectivity in the products are possible. Slow addition of an electrophile such as trimethylsilylchloride allows dynamic resolution under kinetic control (DKR). This