A series of fully functionalized dihydropyridine-3,5-dicarbonitrile derivatives were easily prepared through [2+2+2] annulations of cyanoacetylenes and N-tosylimines in the presence of tertiary phosphine. The scope of the cyclization reaction was investigated, and the high regioselectivity was explained by a rational reaction mechanism.
Key words
phosphine - annulations - cyanoacetylenes -
N-tosylimines - regioselectivity