Chiral-boron-Lewis-acid-catalysed desymmetric ring expansion of 4-substituted cyclohexanones with α-diazomethylphosphonates

Abstract

A method for desymmetrizing asymmetric ring expansion of 4-substituted cyclohexanones with α-diazomethylphosphonates catalyzed by a chiral boron Lewis acid has been developed. The method affords β-ketophosphonate compounds bearing a stereogenic center at the α-position in up to 80% yields, 86% ee, and >20 : 1 dr. The obtained products can be further derivatized, demonstrating the synthetic potential of this reaction.