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A regio- and stereoselective one-pot C–H insertion/olefination protocol has been developed for the late stage installation of α-methylene-γ-butyrolactones into conformationally restricted cyclohexanol-derivatives. The method has been successfully applied in the total synthesis of eudesmanolide natural product frameworks, including α-cyclocostunolide.

A system for the synthesis of α-alkylidene-γ-butyrolactones via a one-pot C–H insertion/olefination sequence is described. The process is based on the rhodium catalysed C–H insertion reaction of α-diazo-α-(diethoxyphosphoryl)acetates. The mild reaction conditions, operational simplicity and ready availability of starting materials are all key features. A wide range of successful reaction systems are reported (41 examples) highlighting the generality of the method. The application of this method in the total synthesis of the natural products (±)-cedarmycins A and B is also described.

The key C-H insertion process of various diazo substrates is achieved in the presence of a dirhodium carboxylate catalyst.