The effect of solvents on hydrosilylation of phenylalkenes catalysed by [RhCl{P(C6H5)3}3]

Abstract

Hydrosilylation of styrene, 2-phenyl-1-propene and trans-1-phenyl-1-propene by trialkylsilicon hydrides of the type CH3R2SiH (R = C2H5, i-C3H7, i-C4H9) catalysed by [RhCl{P(C6H5)3}3] in the presence of benzene, 1,3,5-triethylbenzene, 1,2,3,4-tetraethylbenzene, pentaethylbenzene, hexaethylbenzene, 1,2,3,4-tetrahydronaphthalene, cyclohexane, tetrahydrofurane (THF), tributylphosphate (TBP), dimethylacetamide (DMA), trimethylphosphate (TMP), tributylphosphate (TBP) and hexamethylphosphorictriamide (HMPA) has been studied both in anaerobic conditions and in the presence of air oxygen. Aromatic solvents were found to affect the composition of reaction products similarly as benzene. The use of THF, TBP, TMP, DMA and HMPA as solvents for hydrosilylation of styrene by the above silanes suppresses formation of the α-adduct when the reaction is carried out under anaerobic conditions. The yields of hydrosilylation of 2-phenyl-1-propene and trans-1-phenyl-1-propene by CH3(C2H5)2SiH are decreased by the addition of THF, TBP, TMP and DMA while they are increased by using HMPA as the solvent.