β-Hydrogen eliminations from transition metal alkoxide complexes are well-known organometallic reactions that have often been used to prepare hydride complexes and have been actively explored for catalytic reactions such as transfer hydrogenation and β-alkylation of alcohols. In contrast, analogous β-hydrocarbyl eliminations from metal alkoxides are much less common. It has been demonstrated recently that the reactions can be involved in several novel catalytic processes. However, directly observed β-carbon eliminations from transition metal alkoxides are still rare. 1, 2, 3 We have reported previously that reactions of [Re(dppm)3]I with HC≡CC(OH)RR’ in the presence of HI produced vinyl carbyne complexes [ReI(≡CCH=RR’)(dppm)2]I. To define the reaction mechanism, we have studied the above reactions in neutral condition. These reactions were found to produce a mixture of vinylidene and allenylidene complexes and unexpected products derived from P-C and C-C bond cleavage reactions. We have also explored reactions of [Re(dppm)3]I with internal alkynes R”C≡CC(OH)RR’. Surprisingly, the reactions of [Re(dppm)3]I with R’’C≡CC(OH)RR’ in basic condition generated C-C bond cleaved products cleanly as shown below. In this presentation, the details of the findings are described.

C-C bond activation by rhenium complexes

254th National Meeting (2017)

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