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

A methodology to access chiral cyclic β-ketophosphonates with a stereogenic center at the α-position has been established via an asymmetric desymmetrizing ring-expansion reaction of 4-substituted cyclohexanones with α-diazophosphonates catalysed by a chiral boron Lewis acid.