Manganese allenylidenes

Scheme 5 Synthesis of manganese allenylidenes 5 from 7i-alkyne complex 4...

Preparation of the pioneering manganese(I) allenylidene derivatives [MnCp(=C= C=CR2)(C0)2] (5) was accomplished by treatment of the Ti-aUcyne complex [MnCp ( 7 -HC=CC02Me)(C0)2] (4) with excess of an organolithium reagent, followed by deoxygenation with HCl or COCI2 (Scheme 5) [24,42,95]. In essence, this reaction... 

The nucleophilic character of the allenylidene Cp was experimentally demonstrated for the first time by N. E. Kolobova and co-workers in 1984, who obtained alkenyl-carbyne complexes [MnCp sCC(H)=CR2 (CO)2][X] (R = t-Bu, Ph X = Cl, BF4, CF3C02 ) by treatment of the corresponding neutral manganese(I) alleny-lidenes [MnCp(=C=C=CR2)(CO)2] with Brpnsted acids HX [229]. Since then, a... 

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