THE THERMOLYSIS OF DI-p-TOLYLTITANOCENE AND DI-m-TOLYLTITANOCENE WITH ACETYLENES: FURTHER EVIDENCE FOR ARYNE- OR o-PHENYLENE-TITANOCENE INTERMEDIATES

Article abstract of DOI:10.1016/S0022-328X(00)82879-X

The thermolyses of di-p-tolyltitanocene and di-m-tolyltitanocene with diphenylacetylene, 2-butyne and hexafluoro-2-butyne have been investigated.Di-p-tolyltitanocene reacts with each acetylene to produce a mixture of two isomeric benzotitanoles in approximately equal amounts, whereas di-m-tolyltitanocene and each acetylene afford three isomeric benzotitanoles in an approximate 1 : 1 : 2 ratio, as evidenced by proton NMR analysis of the reaction products.These results lend further evidence for the formation of aryne- or o-phenylene-titanocene intermediates in the thermolyses of diaryltitanocenes.Steric effects play an important role in the addition of acetylene to these intermediates.