1,5-Dipolar electrocyclizations of Thiocarbonyl Ylides bearing C=N groups: Reactions of N-[(Dimethylamino)methylene]thiobenzamide and 2-(Dimethylhydrazono)-1-phenylethane-1-thione with Diazo compounds

Abstract

The reactions of thiobenzamide 8 with diazo compounds proceeded via reactive thiocarbonyl ylides as intermediates, which underwent either a 1,5-dipolar electrocyclization to give the corresponding five-membered heterocycles, i.e., 4-amino-4,5-dihydro-1,3-thiazole derivatives (i.e., 10a, 10b, 10c, cis-10d, and trans-10d) or a 1,3-dipolar electrocyclization to give the corresponding thiiranes as intermediates, which underwent a SNi’-like ring opening and subsequent 5-exo-trig cyclization to yield the isomeric 2-amino-2,5-dihydro-1,3-thi Show more