Cyclopropanation and Isomerization Reactions of β-Diketiminato Boron Complexes

The reaction of HC­[(CBu^t)­(NAr)]₂Li with BCl₃ yielded the azaallyl boron dichloride [ArNC­(Bu^t)­C­(H)­C­(Bu^t)­N­(Ar)]­BCl₂ (1), which can be converted to the β-diketiminato boron dichloride HC­[(CBu^t)­(NAr)]₂BCl₂ (2) upon heating at 40 °C. Reaction of 1 with the bulky lithium salts LiN­(SiMe₃)₂ and MesLi (Mes = 2,4,6-Me₃C₆H₂) resulted in the cyclopropanation of the CBu^t group via the deprotonation of the methyl group, while reactions with PhLi and LiNEt₂ gave substitution products.