Catalyst Repurposing Sequential Catalysis by Harnessing Regenerated Prolinamide Organocatalysts as Transfer Hydrogenation Ligands
作者:Frederic Bourgeois、Jonathan A. Medlock、Werner Bonrath、Christof Sparr
DOI:10.1021/acs.orglett.9b04033
日期:2020.1.3
A catalyst repurposing strategy based on a sequential aldol addition and transferhydrogenation giving access to enantiomerically enriched α-hydroxy-γ-butyrolactones is described. The combination of a stereoselective, organocatalytic step, followed by an efficient catalytic aldehydereduction induces an ensuing lactonization to provide enantioenriched butyrolactones from readily available starting
Histidine-Catalyzed Asymmetric Aldol Addition of Enolizable Aldehydes: Insights into its Mechanism
作者:Ulf Scheffler、Rainer Mahrwald
DOI:10.1021/jo202558f
日期:2012.3.2
Extensive studies of asymmetric cross-aldol addition between enolizablealdehydes are described and provide a deeper insight into histidine-catalyzed aldol additions. In particular, aspects of enantio- as well as diastereoselectivity of these reactions are discussed. Rules and predictions of configurative outcome are explained by using different transition-state models. These discussions are confirmed
Polystyrene-Supported Triphenylsilyl Chloride for the Silylation-Based Kinetic Resolution of Secondary Alcohols
作者:Ravish K. Akhani、Robert W. Clark、Liang Yuan、Li Wang、Chuanbing Tang、Sheryl L. Wiskur
DOI:10.1002/cctc.201500173
日期:2015.5.18
A silyl chloride derivatized styrene polymer was employed in the silylation‐based kineticresolution of secondaryalcohols for chromatography‐free separation of alcohol enantiomers. Synthetically useful selectivity factors were obtained; furthermore, the polymer was recycled for use in a subsequent kineticresolution, and it maintained its selectivity and integrity.
Use and regeneration of reagents using coupled reactions and permselective barriers
申请人:BEND RESEARCH, INC.
公开号:EP0349204A2
公开(公告)日:1990-01-03
A process is disclosed for the use and regeneration of valuable reagents, including coenzymes, using permselective barrier-assisted coupled reactions, most involving redox couples.
Silylation-Based Kinetic Resolution of α-Hydroxy Lactones and Lactams
作者:Robert W. Clark、T. Maxwell Deaton、Yan Zhang、Maggie I. Moore、Sheryl L. Wiskur
DOI:10.1021/ol402982w
日期:2013.12.20
A silylation-based kinetic resolution has been developed for alpha-hydroxy lactones and lactams employing the chiral isothiourea catalyst (-)-benzotetramisole and triphenylsilyl chloride as the silyl source. The system is more selective for lactones than lactams, and selectivity factors up to 100 can be achieved utilizing commercially available reagents.