A new strategy for hyperconjugative antiaromatic compounds utilizing negative charges: a dibenzo[b,f]silepinyl dianion

Abstract

Herein we propose a new strategy for hyperconjugative antiaromatic compounds utilizing negative charges and design the 5,5-diphenyldibenzo[b,f]silepinyl dianion (pseudo 16π-electron system) in which negative hyperconjugation occurs between the anionic π-cloud and the σ*(Si–Ph) orbital. Essentially, reduction of the dibenzo[b,f]silepin with lithium readily generated a dilithium salt of the dibenzosilepinyl dianion, and its hyperconjugative antiaromaticity has been evidenced by the upfield shifts of ¹H NMR signals and theoretical calculations, including large NICS_zz values and ACID plots.