A simple synthesis of substituted N-benzyl-3-pyrrolidinols

An efficient synthesis of N-benzyl-3-hydroxypyrrolidines was achieved by the cyclodehydration of 4-amino-1,2-butanediols using thionyl chloride (SOCl₂). The 4-amino-1,2-butanediols are readily accessible from aldehydes and ketones via homoallylic amines. While the cyclodehydration is non-stereoselective, the diastereomers are easily separated by column chromatography and the N-benzyl-3-pyrrolidinol enantiomers obtainable via Aspergillus Oryzae catalyzed transesterification.