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DOI: 10.1055/sos-SD-002-00576

Mikami, K.; Matsumoto, Y.; Shiono, T.Science of Synthesis, (20032560.

The thermolysis of [Ti(Cp)2(Ph)2] (252) is thought to involve a benzyne intermediate 253 (Scheme 125). In the absence of suitable donor ligands, [Ti(Cp)2(η2-aryne)] species have only a fleeting existence. The thermolysis of [Ti(Cp)2(Ph)2] (252) and following reaction with methylenetriphenylphosphorane proceeds either by CH activation to give ylide complex 254, or by methylene transfer to give titanacyclobutabenzene complex 230 (Scheme 125).[‌370‌] The crystal structure of 254 confirms that the adopted conformation maximizes the π-interaction between titanium and the ylide carbon atom.[‌345‌] The compound does not react with ketones. Reactions of the benzyne intermediate 253 with metalcarbonyl complexes lead to titanium-substituted Fischer carbene complexes such as 255 (Scheme 125). The zirconium analogues are similarly accessible.[‌371‌]

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