Synthesis of optically active 5-substituted-2-pyrrolidinone derivatives having atropisomeric structure and 3,5-cis-selective reaction of their enolates with electrophiles

Optically pure forms (≥98% ee) of N-(o-tert-butylphenyl)-5- (methoxymethyl)-2-pyrrolidinone having atropisomerism and N-(o-tert- butyldiphenylsiloxyphenyl)-5-(methoxymethyl)-2-pyrrolidinone having an atropisomerism-like structure were prepared from ortho-substituted aniline derivatives and (S)-5-(methoxymethyl)butyrolactone in a stereoselective manner. The reactions of Li-enolates from these lactams with various electrophiles and subsequent dearylation of the products gave 3,5-cis- disubstituted-2-pyrrolidinone derivatives.