Ruthenium-Catalyzed [2 + 2] Cycloaddition of Allenynes Leading to a Bicyclo[4.2.0]octa-1(8),5-diene Skeleton
journal contributionposted on 17.09.2009, 00:00 by Nozomi Saito, Yuki Tanaka, Yoshihiro Sato
The reaction pathway of Cp*RuCl(cod)-catalyzed cyclization of allenynes was dramatically changed depending on the type of solvent employed. That is, while a cyclodimerization of allenyne proceeded to give a pentacyclic compound in toluene, a bicyclo[4.2.0]octa-1(8),5-diene derivative was exclusively produced by [2 + 2] cycloaddition of allenyne in methanol. It was also demonstrated that the [2 + 2] cycloaddition was catalyzed by a cationic ruthenium complex generated from Cp*RuCl(cod) and methanol in situ.