Zinc‐Catalyzed Synthesis of Allylsilanes by Si−H Bond Insertion of Vinyl Carbenoids Generated from Cyclopropenes

Abstract

Allylsilanes have long been recognized as valuable building blocks for organic synthesis. A zinc-catalyzed reaction of cyclopropenes and hydrosilanes provides a convenient route to these versatile unsaturated organosilanes. In this transformation, ZnBr serves as an efficient catalyst, allowing the generation of a zinc vinyl carbenoid intermediate, which is subsequently involved in a Si-H bond insertion. The process shows broad scope, and is amenable to substituted and functionalized cyclopropenes or the functionalization of polysiloxanes. Moreover, zinc-catalyzed carbene insertion into a Ge-H bond is reported for the first time.

Synthesis of Bifunctional Allylic Compounds by Using Cyclopropenes as Functionalized Allyl Equivalents

“…As stated above, formation of compounds 3 might involve a rhodium carbene intermediate generated from 1 , which evolves through Si−H bond insertion . However, additional interesting features were revealed by routine experiments (Scheme ).…”

“…While allylsilanes and allyl alcohols themselves are easily accessible, scaffold A is far less common. Considering interesting features of structure A and relying on previous studies, we devised a simple route for the synthesis of A through Si−H bond carbene insertion. While silyl fragment B is elementary, selection of a carbene‐fragment precursor seems less obvious.…”

“…Pleasantly, optimized conditions led again to the corresponding aminoderivatives 8a-d in generally good yields (55-93%, Scheme 3, B). As stated above, formation of compounds 3 might involve a rhodium-carbene intermediate generated from 1, [5,7] which evolves via Si-H bond insertion. [6,10] However, additional interesting features were revealed by routine experiments (Scheme 4).…”

Synthesis of Bifunctional Allylic Compounds by Using Cyclopropenes as Functionalized Allyl Equivalents

“…As stated above,formation of compounds 3 might involve ar hodium carbene intermediate generated from 1, [5,7] which evolves through SiÀHb ond insertion. [6,10] However,a ddi-tional interesting features were revealed by routine experiments (Scheme 4).…”

“…While allylsilanes and allyl alcohols themselves are easily accessible,s caffold A is far less common. Considering interesting features of structure A and relying on previous studies, [5] we devised as imple route for the synthesis of A through SiÀHb ond carbene insertion. While silyl fragment B is elementary,s election of ac arbenefragment precursor seems less obvious.H owever,u sing adequately decorated cyclopropene C, [6,7] which can be routinely prepared, [8] carbene intermediate D might be accessible,t hereby providing access to desired scaffold A (Scheme 1A).…”