Double Group Transfer Reactions of an Unsaturated Tantalum Methylidene Complex with Pyridine <i>N</i>-Oxides

Abstract

The electrophilic nature of the benzamidinate tantalum methylidene complex [TolC(NSiMe 3 ) 2 ] 2 Ta(CH 2 )CH 3 ( 1 ) allows for reactivity with pyridine N -oxides, which leads to the formation of the tantalum oxo complex [TolC(NSiMe 3 ) 2 ] 2 Ta(O)CH 3 ( 5 ) and methylpyridines; treatment of 1 with the related nitrone species N - tert -butyl-α-phenylnitrone leads to overall different products. Mechanistic studies show the reactions proceed via regioselective methylene group transfer to the pyridine N -oxides.