Convenient preparation of silylboranes

(Triorganosilyl)pinacolboranes were prepared by reaction of triorganosilyll ithium reagents with pinacolborane or isopropoxypinacolborane in high yield . The reaction also is applicable to synthesis of 2-(triorganosilyl)-4,4,6- trimethyl-1,3,2,-dioxaborinane. A new germylborane derivative was similarly prepared from the corresponding germyllithium.