title: Diastereoselective Radical Hydrogen Transfer Reactions using N-Heterocyclic Carbene Boranes.
abstract: Reported herein are the first diastereoselective and Lewis acid-mediated radical reactions of N-heterocyclic carbene (NHC) boranes. We applied these reactions to the synthesis of four propionate diastereoisomers combining an aldol reaction, followed by a stereoselective radical-based reduction in which the NHC borane serves as the hydrogen donor, thus obviating the use of tin-based reagents. The 2,3-syn isomer is obtained by combining an NHC-borane and a Lewis acid (MgBr2·OEt2), while using a reverse polarity strategy provides the 2,3-anti isomer.
authors.affiliation: Bio-Organic Chemistry Laboratory, Institut de Recherches Cliniques de Montréal (IRCM) , Montréal, Québec H2W 1R7, Canada.|Département de Chimie, Université de Montréal , Montréal, Québec H3C 3J7, Canada.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Tambutet
authors.affiliation: Bio-Organic Chemistry Laboratory, Institut de Recherches Cliniques de Montréal (IRCM) , Montréal, Québec H2W 1R7, Canada.|Département de Chimie, Université de Montréal , Montréal, Québec H3C 3J7, Canada.|Department of Chemistry, McGill University , 801 Sherbrooke Street West, Montreal, Québec H3A 2K6, Canada.
authors.forename: Yvan
authors.initials: Y
authors.lastname: Guindon