Eight-Membered Carbocycles from a Dötz-Like Reaction

Abstract

The geometric restraints of the cyclobutene moiety in the starting complex, a Fischer dienyl carbene complex, are presumably the reason for the surprising formation of eight-membered carbocycles in the reaction of these complexes with alkynes [Eq. (1)]. In contrast to the Dötz reaction, here an eight-electron, rather than a six-electron, cyclization occurs.