Cleavage of Both C(sp(3))-C(sp(2)) Bonds of Alkylidenecyclopropanes: Formation of Ethylene-Osmium-Vinylidene Complexes

Castro-Rodrigo R; Esteruelas MA; Lopez AM; Lopez F; Mascarenas JL; Olivan M; Onate E; Saya L; Villarino L

Journal of the American Chemical Society, Vol.132, No.2, 454-454, 2010

Castro-Rodrigo R, Esteruelas MA, Lopez AM, Lopez F, Mascarenas JL, Olivan M, Onate E, Saya L, Villarino L

The complex [OsTp(kappa(1)-OCMe)(2)((PPr3)-Pr-i)]BF4 [Tp = hydridotris(pyrazolyl)borate] promotes the cleavage of both C(sp(3))-C(sp(2)) bonds of benzylidenecyclopropane and 3-phenylpropylidenecyclopropane to yield the complexes [OsTp(=C=CHR)(eta(2)-CH2=CH2)((PPr3)-Pr-i)]BF4 (R = Ph, CH2CH2Ph). The process is proposed to take place via metallacyclopropene intermediates stabilized by an ethylene chelation assistant. The driving force for the fragmentation is the high stability of the resulting ethylene-Os-vinylidene species.