A One-Pot C–H Insertion/Olefination Sequence for the Formation of α-Alkylidene-γ-butyrolactones

A one-pot C-H insertion/olefination sequence for the conversion of α-diazo-α-(dialkoxyphosphoryl)acetates into α-alkylidene-γ-butyrolactones is reported. The key C-H insertion process is achieved using a catalytic amount of a dirhodium carboxylate catalyst, using operationally simple conditions. The size and electronic properties of the attached substituents were found to influence the regio- and diastereoselectivity of the process. The utility of the process is demonstrated by the synthesis of a known Staphylococcus aureus (MRSA) virulence inhibitor.