Base-controlled divergent oxidative dimerization of allomaltol-containing enolates: access to distinct diastereomers of 1,4-diketones.

In the present communication, a novel synthetic approach to allomaltol-containing 1,4-diketones has been developed. The strategy relies on oxidative enolate coupling of the corresponding ketones and enables diastereodivergent synthesis controlled by the nature of the base. Depending on the base employed, two distinct diastereomers (meso and racemic forms) are selectively obtained from the same starting material. Their interconversion under various conditions was demonstrated, indicating thermodynamic control of the stereochemical outcome. The structures of both diastereomers were unambiguously established via X-ray analysis. Furthermore, the synthesized 1,4-diketones serve as versatile precursors for a series of novel tetrasubstituted furan derivatives.