Toward a Chemical Constructor: A Lego-Like Approach for Formal α-Alkylation of Cyclic Ketones

Abstract

A conceptual strategy for a formal α-alkylation of α-methylene ketones was developed. Diverse 1°and 2°alkyl substituents were generated in the α-position of various ketones via synthesis of enaminone (step 1) and treatment with organomagnesium (step 2) with subsequent catalytic hydrogenation (step 3, 1°alkyl) or organocopper reagents (step 4, 2°alkyl). Tolerance toward ester, Boc-protected amine, and α-fluoro-substituted ketone moieties was demonstrated. The suitability of the method for late-stage natural product modification was shown.