An iridium-catalyzed C(sp3)-H borylation of X3SiMe (X = hydrolyzable group) was established. A trialkoxy(methyl)silane bearing sterically demanding neopentyloxy groups (X = neopentyloxy) underwent C-H borylation at the methyl group on silicon, giving (borylmethyl)tris(neopentyloxy)silane in 70% isolated yield. The choice of the hydrolyzable group X was the key to efficient and chemoselective C-H borylation; trialkoxy(methyl)silanes bearing sterically less demanding alkoxy groups (X = ethoxy, n-butyloxy, and isobutyloxy) suffered from C-H activation at the alkoxy groups, and trichloro(methyl)silane (X = Cl) failed to react. A trimethylsiloxy group could substitute the neopentyloxy groups of the borylated product by the reaction of trimethylsilanol in the presence of tetrabutylammonium fluoride.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry