Tri(cyclohexa-2,5-dien-1-yl)silane: A Stable and Easy-to-handle Surrogate of Monosilane (SiH₄)

Oestreich et al. have reported that tri(cyclohexa-2,5-dien-1-yl)silane (1) acts as a surrogate of monosilane (SiH₄). According to their results, in the presence of catalytic amounts of B(C₆F₅)₃, an allylic hydride of cyclohexa-2,5-dienyl groups of 1 is transferred to form an Si-H bond-substituted silane (2) with the release of a molecule of benzene. Sequential B(C₆F₅)₃-catalyzed further replacement of two remaining cyclohexa-2,5-dienyl moieties by Si-H bonds proceeds smoothly and monosilane is released.　The given monosilane is directly applied to the transfer hydrosilylation of alkenes. Generally, the handling of monosilane is quite difficult because it is a pyrophoric and toxic gas. On the other hand, 1 is a safe and easy-to-handle monosilane surrogate which easily generates monosilane in situ. Therefore, 1 is expected to be used in organic synthesis in the future.