Installation of α-ketocarboxylate groups to C7-position of indolines via C−H addition and oxidation approach under ruthenium catalysis

The ruthenium(II)-catalyzed site-selective acylation of indolinic C−H bonds with ethyl glyoxalate is described. A cationic ruthenium catalyst in the presence of copper(II) acetate was found to be an optimal catalytic system for the construction of C7-indolinyl ketoesters. In this process, C−H addition reaction first takes place, and subsequent oxidation of alcohol intermediates occur in-situ. The formed C7−functionalized indolines can be a crucial array towards the construction of novel bioactive molecules.

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