^MeCAAC=N⁻: A Cyclic (Alkyl)(Amino)Carbene Imino Ligand

Abstract

A cyclic (alkyl)(amino)carbene (CAAC) has been shown to react with a covalent azide similar to the Staudinger reaction. The reaction of ^Me CAAC with trimethylsilyl azide afforded the N-silylated 2-iminopyrrolidine (^Me CAAC=NSiMe₃ ), which was fully characterized. This compound undergoes hydrolysis to afford the 2-iminopyrrolidine and trimethylsiloxane which co-crystallize as a hydrogen-bonded adduct. The N-silylated 2-iminopyrrolidine was used to transfer the novel pyrrolidine-2-iminato ligand onto both main-group and transition-metal centers. The reaction of the tetrabromodiborane bis(dimethyl sulfide) adduct with two equivalents of ^Me CAAC=NSiMe₃ afforded the disubstituted diborane. The reaction of ^Me CAAC=NSiMe₃ with TiCl₄ and CpTiCl₃ afforded ^Me CAAC=NTiCl₃ and ^Me CAAC=NTiCl₂ Cp, respectively.