Rhodium-Catalyzed Intermolecular Silylation of Csp-H by Silacyclobutanes

The signature reactivity of silacyclobutane (SCB) is their cycloaddition reactions with various pi bonds. Recently, the first cases were disclosed where SCBs reacted with both C-sp2-H and C-sp3-H sigma bonds in an intramolecular fashion. Herein, it is reported that SCB is also an efficient reagent for C-sp-H bond silylation. Thus, rhodium-catalyzed intermolecular reactions between SCBs and terminal alkynes produced a series of symmetrical and unsymmetrical tetraorganosilicons bearing a C-sp-Si functionality. Preliminary studies suggested that the reaction did not involve a cycloaddition pathway, but instead a direct activation of C-sp-H bonds.