NITROSOARENE AND NITROSOALKANE INSERTION REACTIONS OF TITANACYCLOBUTENES

Titanacyclobutenes react with 2-methyl-2-nitrosopropane and nitrosoare nes to afford products of insertion into the Ti-CH2 bond of the metall acycle. Structural confirmation was obtained through single crystal X- ray diffraction analysis of the insertion product of the diphenyltitan acyclobutene and 2-methyl-2-nitrosopropane: C29H31NOTi, monoclinic, P2 (1)/n, a = 7.984(2), b = 20.383(8), c = 15.005(4) angstrom, beta = 100 .55(2)-degrees, V = 2400(2) angstrom-3, Z = 4. The insertion products display dynamic NMR behavior consistent with pyramidal inversion at ni trogen, with activation barriers of c. 14 kcal mol-1. Hydrolysis of th e insertion products affords the corresponding hydroxylamines, while t reatment of them or of the titanacyclobutenes with excess nitrosoarene results in metallacycle degradation and formation of azoxyarene.