Silyl Group Effect at C2 Position on the Reactivity of Cyclopentane-1,3-diyl

Abstract

2-Silyl group effect on the reactivity of cyclopentane-1,3-diyl has been investigated in detail. Theory predicts that (1) the 2,2-disilyl 1,3-diradicals possesses the singlet ground state spin-multiplicity and (2) the paired electrons are occupied preferentially in the antisymmetric NBMO (Ψ_A). Thus, the silyl-substituted singlet cyclopentane-1,3-diyl is expected to give not the intramolecular cyclization product, but the silyl-migration product. Indeed, the experimentally generated 2-silylcyclopentane-1,3-diyl affords quantitatively the 5-silylcyclopentene derivative.