Reaction between mono-olefins and ferrocenylcarbene complexes of chromium; formation of 3-amino- and 5-amino-pent-1-enes

Abstract

The reactions of 1,1-diphenylethylene and dimethyl fumarate with the carbene complexes, [(CO)₅CrC(X)Fc](X = OMe or NC₄H₈, Fc = ferrocenyl) at 136° in a nitrogen atmosphere are described. Although the methoxy-compound reacts with dimethyl fumarate to give a 1-ferrocenyl-1-methoxycyclopropane derivative in 50% yield, the pyrrolidinyl compound reacts with dimethyl fumarate to give dimethyl 5-[ferrocenyl(pyrrolidin-1-yl)methyl]-3,4-bis-methoxycarbonylhex-2-enedioate (32%) and with 1,1-diphenylethylene to give 3-ferrocenyl-1,1,5,5-tetraphenyl-3-pyrrolidin-1-ylpent-1-ene (7%). The course of these reactions is discussed briefly and it is suggested that they are not consistent with the participation of a free carbene species, Fc(X)C:. The intervention of zwitterionic intermediates in the reactions of aminocyclopropanes is considered.