Synthesis, structure and reactivity of a boron-containing spirocycle carbanion

Abstract

The crystal structure, electronic characteristic, as well as the formation process, and nucleophilic reactivity of an unexpected boron-containing carbanion are presented. Its structure consists of a discrete cation and a spirocycle structure, in which the sp 3 hybrid C7 atom connects the mesityl substituted oxaborole unit and the puckered anthracene moiety. • A novel boron-containing carbanion with distinct structural characteristics was synthesized, which was composed of a discrete [K(cryptand)] + ion and a spirocycle anion. • The formation and electronic structure of carbanion were explored through DFT calculations. • The nucleophilic reactivity of carbanion with some chlorosilane or halogenated alkanes in THF solution was evaluated. Carbanion ( 2 ) was synthesized by the deprotonation strategy through treatment of (2-(anthracen-9-yl)phenyl)(hydroxy)(mesityl)borane ( 1-H ) with KN(SiMe 3 ) 2 in the presence of [2,2,2]-cryptand in tetrahydrofuran (THF) solution followed by crystallization of the crude product from cooled THF. Its crystal structure and electronic properties are presented, as well as the formation process and nucleophilic reactivity with chlorosilane or halogenated alkanes.