Silylative Coupling of Vinyl Alkyl Ethers with Vinylsilanes Catalyzed by Ruthenium Complexes

Abstract

Ruthenium complexes such as RuHCl(CO)(PPh3)3 (I), RuCl(SiMe3)(CO)(PPh3)2 (II), RuCl2(PPh3)3 (III), and Ru(CO)3(PPh3)2 (IV) appear to be very effective catalysts of cross-disproportionation of vinyl-trisubstituted silanes CH2CHSiR3 (where R3 = Me3, PhMe2, (OEt)3) with vinyl alkyl ethers CH2CHOR‘ (where R‘ = ethyl, n-propyl, n-butyl, tert-butyl, tert-pentyl, 2-ethylhexyl, cyclohexyl, trimethylsilyl) to yield a mixture (E+Z) of 1-silyl-2-alkoxyethenes. Stoichiometric insertion of vinyl n-propyl ether into Ru−Si bonds of II and MS study of the products of the deuterated vinyltrimethylsilane with vinyl ethyl ether indicate that the mechanism of cross-disproportionation involves a migratory insertion of the vinyl ether into the Ru−Si bond (and vinylsilane into the Ru−H bond) followed by β-H (and β-Si) transfer to eliminate 1-triorganosilyl-2-alkoxyethenes (and ethene).