A brief and efficient approach for the synthesis of (±)‐5‐benzyl‐4‐hydroxy‐2‐pyrrolidine (1) from phenylalanine racemate is described. The key step is the stereocontrolled reduction of the keto functionality of benzylated pyrrolidinone intermediate (6) via sodium borohydride in carboxylic acid medium furnishing both (R,R)‐ and (S,S)‐configured diastereomers. The natural (R,R) enantiomer (2), however, crystallized out from its racemic mixture. Structure of 2 was confirmed by NMR, IR, elemental analyzer, and single crystal X‐ray crystallographic techniques.

A short approach for the synthesis of 3,4‐fused γ‐lactone‐γ‐lactam bicyclic systems (1) in diastereomeric mixtures from chiral D‐alanine methyl ester hydrochloride is described. The key step towards lactonisation is the reduction of the carbonyl ketone of the 5R‐configured 3,5‐dimethylpyrrolidine‐2,4‐dione diastereomers (8) via sodium borohydride in the presence of hydrochloric acid. With the presence of ethyl acetyl functionality at C3‐position, ester hydrolysis of 8 occurred concomitantly with keto reduction leading to lactonisation and eventually affording the anticipated (3S,4S,5R), (3R,4R,5R), (3R,4S,5R) and (3S,4R,5R) bicyclic moieties. The formation of the fused systems was confirmed by mass spectroscopy (MS) and nuclear magnetic resonance (NMR) analyses.

A short synthesis of the natural (4R,5R)‐streptopyrrolidine (I) and its unnatural (4S,5S) enantiomer is described.