A study of the 1,2-addition of group IV metallacycles derived from 1-alkynylphosphonates to conjugated enones

Addition of group IV cyclopropenemetallocycles to conjugated enones indicates that the reaction course is mostly dependent on the metallocyle and the enone moiety. The zirconacycle affords the unrearranged products . On the other hand, some rearranged products, 1,3-butadienylphosphonates, are obtained when titanacycles are used.