Bi(cyclopentyl)diol-Derived Boronates in Highly Enantioselective Chiral Phosphoric Acid-Catalyzed Allylation, Propargylation, and Crotylation of Aldehydes
作者:Jinping Yuan、Pankaj Jain、Jon C. Antilla
DOI:10.1021/acs.joc.0c01646
日期:2020.10.16
catalytic addition of bi(cyclopentyl)diol-derived boronates to aldehydes promoted by chiralphosphoricacids, allowing for the formation of enantioenriched homoallylic, propargylic, and crotylic alcohols (up to >99% enantiomeric excess (ee), diastereomeric ratio (dr) >20:1). These boronate substrates provided superior enantioselectivities, allowing for the reactions to proceed with low catalyst loading
Brønsted Acid Catalyzed Asymmetric Propargylation of Aldehydes
作者:Pankaj Jain、Hao Wang、Kendall N. Houk、Jon C. Antilla
DOI:10.1002/anie.201107407
日期:2012.2.6
Which gets activated? A versatile and highly enantioselective chiral Brønstedacidcatalyzed method for the propargylation of aldehydes is described to provide a range of chiral homopropargylic alcohols. Computational studies support the belief that the chiral phosphoric acid activates the allenyl boronic acid pinacol ester reagent rather than the aldehyde.
Enantioselective Carbonyl Propargylation by Iridium-Catalyzed Transfer Hydrogenative Coupling of Alcohols and Propargyl Chlorides
作者:Sang Kook Woo、Laina M. Geary、Michael J. Krische
DOI:10.1002/anie.201203334
日期:2012.7.27
It takes alkynes! Exposure of propargylchlorides to primary benzylic alcohols in the presence of [Ir(cod)(R)‐segphos}]OTf (cod=1,5‐cyclooctadiene, segphos=5,5′‐bis(diphenylphosphino)‐4,4′‐bi‐1,3‐benzodioxole, Tf=trifluoromethanesulfonyl) results in hydrogen exchange to give allenyliridium–aldehyde pairs that combine to form products of propargylation with high ee value (see scheme). The reaction