Copper-Catalyzed Markovnikov Selective 3,4-Hydrosilylation of 2-Substituted 1,3-Dienes

Abstract

A copper-catalyzed regioselective Markovnikov 3,4-hydrosilylation of 2-substituted 1,3-dienes has been accomplished. A wide range of 2-substituted 1,3-dienes and trihydrosilanes are compatible under the optimal conditions. The bisphosphine ligand with a rigid backbone provides the Markovnikov 3,4-hydrosilylation product in better yield and selectivity. Besides, the synthetic utilities of the allylsilanes also were demonstrated by their flexible derivatizations.

Dirhodium(II)/DPPM Catalyzed 1,2-Hydrosilylation of Conjugated Dienes with Tertiary Silanes

“…Conjugated dienes could undergo 1,4- or 1,2-hydrosilylation with either Markovnikov or anti-Markovnikov addition depending on the catalyst (Scheme , a) . In the past decades, a variety of transition metal catalysts, such as Pt, Rh, Pd, Fe, Co, Ni, Cu, and Ti have been developed for 1,4-hydrosilylation of 1,3-dienes, due to the tendency to form π-allyl transition metal intermediates. For diene 1,2-Markovnikov hydrosilylation, numerous ligand-controlled transition metal catalysts have been developed in recent years .…”

Ligand-controlled regiodivergence in cobalt-catalyzed hydrosilylation of isoprene

“…Particularly, due to the weak electronic and steric effect of the methyl substituent, the regioselective hydrosilylation reaction of isoprene is an extremely challenging task (Scheme 1a). 9 f ,10 In most cases, the reported hydrosilylation reactions of isoprene produced a mixture of isomers with poor to moderate regioselectivity (<10 : 1 rr). 11 Very limited examples were exploited successfully with good regioselective control.…”

Copper-Catalyzed Enantioselective Hydrosilylation of Allenes to Access Axially Chiral (Cyclohexylidene)ethyl Silanes

“…Various transition-metal-catalyzed enantioselective hydrosilylations of unsaturated compounds have been established as a powerful tool for synthesizing enantioenriched organosilicon compounds. − Among them, copper catalysts, albeit with the advantages of low toxicity and easy availability, have been less explored in asymmetric hydrosilylation so far . On the basis of our previous studies of C–Si bond formation and copper-catalyzed hydrosilylation of allenes (Scheme c), herein we disclose a new method for preparing axially chiral cyclohexylidene derivatives by copper-catalyzed enantioselective hydrosilylation of prochiral 4-substituted vinylidenecyclohexanes (Scheme d).…”

“…To improve our understanding of the regioselectivity of the current allene hydrosilylation, a plausible mechanism is proposed in Scheme . On the basis of the precedent of copper-catalyzed hydrosilylation of unsaturated compounds, a reactive Cu–H intermediate is likely involved (Scheme a). , Initially, Cu–H species I was generated in the presence of a copper catalyst, which then coordinates with allene to generate Cu complex II . Considering the steric effect, the formation of complex III is unfavorable.…”