Access to Quaternary-Substituted Cyclobutylsilanes by Ring Opening of Arylbicyclobutanes with Silyllithium Reagents

Disclosed herein is the reaction of silyllithium reagents with quaternary-substituted arylbicyclobutanes to diastereoselectively form polysubstituted cyclobutylsilanes by C−C bond cleavage. The bicyclobutanes are generated in situ, by lithium-halogen exchange, from readily accessible (bromomethyl)iodocyclopropane precursors, rendering this a one-pot transformation. The trapping of a generated cyclobutyllithium intermediate with an electrophile was also demonstrated, providing a cyclobutane product with vicinal quaternary stereocenters. The utility of the cyclobutylsilane products was showcased by Tamao−Fleming oxidation to prepare a quaternary-substituted cyclobutanol.