the reaction of allyl acetate with the anionic species prepared from various N-(2-tert-butylphenyl)sulfonamides and NaH proceeded in an enantioselective manner (up to 95% ee) to give optically active N-allylated sulfonamide derivatives possessing an N–C axially chiral structure in high yields.
Importantly, a simple oxidation of N,O-acetal moiety and γ-addition to the versatile atropoisomeric iminium ion enabled diversity-synthesis of various valuable axially chiral sulfonamides and anilides. For example, γ-azidation of the iminium ion opened an opportunity to the synthesis of atropoisomeric non-natural amino acid derivatives and an axially chiral 8-membered cyclic sulfonamide was finally synthesized