Base-Mediated Cyclizationof N -BenzylKetimines with Diynes: Conditions-Controlled Switching between N -Vinyl Pyrroles and 2 H -Azepines

Abstract

Abstract Semistabilized azaallyl anions, generated from N-benzyl ketimines in the NaOtBu/DMSO superbase medium, undergo conditions-controlled formal [3 + 2] or [4 + 3] cyclization with diaryldiynes. Consequently, selective switchable syntheses of triarylsubstituted α-arylated N-vinyl pyrroles (in up to 64% yield) and tetraarylated 2H-azepines (in up to 75% yield) have been developed. The synthetic value of this strategy has been validated by successful gram-scale syntheses of both products.