A fast, efficient and stereoselective synthesis of hydroxy-pyrrolidines
摘要:
A five-step, protecting group free synthesis of 2,3-cis substituted hydroxy-pyrrolidines is presented. Key steps in the synthesis are the chemoselective formation of a primary amine via a Vasella reductive amination using ammonia as the nitrogen source, and the stereoselective formation of a cyclic carbamate from an alkenylamine. Improvement of the reductive amination, by way of the use of alpha-picoline borane as a more environmentally benign reducing agent, is also presented. (C) 2010 Elsevier Ltd. All rights reserved.
times but comparable yields and selectivity. We report substantially improved reaction conditions for palladium(II)-catalyzed tandem cyclization–intramolecular oxycarbonylation of (amino)polyols with a terminal double bond, based on utilization of iron pentacarbonyl [Fe(CO)5] as an affordable and safe liquid supply of the carbonyl unit fully replacing gaseouscarbonmonoxide. Direct comparison with the