Facile hydrosilylation of norbornadiene by silanes R 3SiH and R 2SiH 2 with molybdenum catalysts

Abstract

Photochemically activated [Mo(CO) 6] and [Mo(CO) 4(η 4-nbd)] have been demonstrated to be very effective catalysts for hydrosilylation of norbornadiene (nbd) by tertiary (Et 3SiH, Cl 3SiH) and secondary (Et 2SiH 2 and Ph 2SiH 2) silanes to give 5-silyl-2-norbornene, which under the same reaction conditions transform in ring-opening metathesis polymerization (ROMP) to unsaturated polymers and to a double hydrosilylation product, 2,6-bis(silyl)norbornane. The yield of a particular reaction depends very strongly on the kind of silane involved. The reaction products were identified by means of chromatography (GC–MS) and 1H and 13C NMR spectroscopy. In photochemical reaction of [Mo(CO) 4(η 4-nbd)] and Ph 2SiH 2 in cyclohexane- d 12, η 2-coordination of the Si H bond to the molybdenum atom is supported by 1H NMR spectroscopy due to the detection of two equal-intensity doublets with 2 J H H = 5.4 Hz at δ 6.12 and −5.86 ppm.