Kinetic Resolution of Tertiary Alcohols: Highly Enantioselective Access to 3-Hydroxy-3-Substituted Oxindoles
作者:Shenci Lu、Si Bei Poh、Woon-Yew Siau、Yu Zhao
DOI:10.1002/anie.201209043
日期:2013.2.4
Enantioselective: The first highlyenantioselectivekineticresolution of 3‐hydroxy‐3‐substituted oxindoles has been developed through oxidative esterification catalyzed by a N‐heterocyclic carbene (see picture). This method uses a simple procedure and provides 3‐hydroxy‐oxindoles with various substituents at the 3‐position in excellent enantiopurity. S=selectivity.
The Importance of 1,5‐Oxygen⋅⋅⋅Chalcogen Interactions in Enantioselective Isochalcogenourea Catalysis
作者:Claire M. Young、Alex Elmi、Dominic J. Pascoe、Rylie K. Morris、Calum McLaughlin、Andrew M. Woods、Aileen B. Frost、Alix Houpliere、Kenneth B. Ling、Terry K. Smith、Alexandra M. Z. Slawin、Patrick H. Willoughby、Scott L. Cockroft、Andrew D. Smith
DOI:10.1002/anie.201914421
日期:2020.2.24
5-O⋅⋅⋅chalcogen (Ch) interactions in isochalcogenourea catalysis (Ch=O, S, Se) is investigated. Conformational analyses of N-acyl isochalcogenouronium species and comparison with kinetic data demonstrate the significance of 1,5-O⋅⋅⋅Ch interactions in enantioselective catalysis. Importantly, the selenium analogue demonstrates enhanced rate and selectivity profiles across a range of reaction processes including
Pentanidium–Catalyzed Enantioselective α-Hydroxylation of Oxindoles Using Molecular Oxygen
作者:Yuanyong Yang、Farhana Moinodeen、Willy Chin、Ting Ma、Zhiyong Jiang、Choon-Hong Tan
DOI:10.1021/ol302030v
日期:2012.9.21
Pentanidium-catalyzed alpha-hydroxylation of 3-substituted-2-oxindoles using molecular oxygen has been developed with good yields and enantioselectivities. This reaction does not require an additional reductant such as triethyl phosphite, which was typically added to reduce the peroxide intermediate. The reaction was demonstrated to consist of two-steps: an enantioselective formation of hydroperoxide oxindole and a kinetic resolution of the hydroperoxicle oxindole via reduction with enolates generated from the oxindoles.