Robust Synthesis of N-Sulfonylazetidine Building Blocks via Ring Contraction of α-Bromo N-Sulfonylpyrrolidinones

Abstract

A simple and robust one-pot nucleophilic addition-ring contraction of α-bromo N-sulfonylpyrrolidinones has been achieved toward α-carbonylated N-sulfonylazetidines. In the presence of potassium carbonate, various nucleophiles, such as alcohols, phenols or anilines, have been efficiently incorporated into the azetidine derivatives. Moreover, the α-bromopyrrolidinone precursors could be selectively obtained in good yields by monobromination of cheap and easily available N-sulfonyl-2-pyrrolidinone derivatives.

A General Strategy for the Synthesis of Enantiomerically Pure Azetidines and Aziridines through Nickel‐Catalyzed Cross‐Coupling

“…Examples of ring expansion of aziridines with dimethylsulfoxonium methylide have also been demonstrated 1. Recently, a three‐step protocol based on ring contraction of α‐bromo pyrrolidinones to give racemic α‐carbonylated azetidines was reported 6. More common synthetic strategies rely on 4‐ exo cyclizations of open‐chain structures 1d.…”

Recent advances in synthetic facets of immensely reactive azetidines

“…Blanc and co-workers 46 have reported the synthesis of a-carbonylated N-sulfonylazetidines via ring contraction of a-bromo N-sulfonylpyrrolidinones (Scheme 36). The synthetic methodology involved the ring contraction of a-bromo N-sulfonylpyrrolidinone 166 with K 2 CO 3 in presence of acetonitrile : methanol (9 : 1) to yield the a-carbonylated Nsulfonylazetidine 167 exclusively.…”

Facile and Green Synthesis of Saturated Cyclic Amines

“…In the presence of potassium carbonate, the reaction involves the nucleophilic addition mediated ring contraction reactions of α-bromo N -sulfonylpyrrolidinones. They managed to synthesize variously substituted azitidine derivatives using nucleophiles like anilines, phenols and alcohols ( Scheme 15 ) [ 31 ].…”