Heterocycles, acylation reduction with metals

A different type of metallation, directed by an acyl group at either the pyridine 3- or 4-position, uses a catalytic ruthenium complex and results in a reductive Heck-type substitution, as illustrated below. The mechanism involves insertion of the metal into a C-H bond. The process is non-polar and works equally well with electron-rich heterocycles, for example indole. ... 

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