B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-Catalyzed Diastereoselective Formal (4 + 1)-Cycloaddition of Vinylcyclopropanes and Et<sub>2</sub>SiH<sub>2</sub>
Peng‐Wei Long, Martin Oestreich
Abstract
A formal (4 + 1)-cycloaddition of vinylcyclopropanes and Et2SiH2 to afford 3,4-disubstituted silolanes is reported. The reaction sequence commences with the known B(C6F5)3-catalyzed alkene hydrosilylation with dihydrosilanes. Cleavage of the remaining Si–H bond in the hydrosilylation product assisted by B(C6F5)3 leads to formation of a cyclopropane-stabilized silylium ion. The activated cyclopropane ring is then opened by the in situ-generated borohydride accompanied by ring closure to the silolane. The diastereoselectivity is rationalized by a mechanistic model.
Topics & Concepts
HydrosilylationCyclopropaneCycloadditionChemistryAlkeneRing (chemistry)CatalysisCleavage (geology)Medicinal chemistryBond cleavageStereochemistryBorohydrideOrganic chemistryGeotechnical engineeringFracture (geology)EngineeringOrganoboron and organosilicon chemistryCyclopropane Reaction MechanismsCatalytic C–H Functionalization Methods