Enantioselective Synthesis of 2-Substituted Pyrrolidines from 4-Hydroxynitriles. Application to the Synthesis of the Dopamine Agonist rs-59022

Abstract

Two novel routes to optically active 4-hydroxynitriles and the subsequent cyclization to 2-substituted pyrrolidines are described. The methodology is applied to the synthesis of the key intermediate used in the synthesis of the dopamine agonist RS-59022. Unusual selectivity in the CBS reduction of 4-oxonitriles is explained through structural and mechanistic analysis.