The first examples of intramolecular cyclopropanation reactions on a phosphonate template catalyzed by Rh2 (OAc) 4 are described. These reactions proceed in excellent yield and give mixtures of the P-heterocycles cis-2a-d and trans-2a-d with moderate levels of diastereoselectivity. The diastereoselectivity of this tranformation is dependent upon the size of the alkyl group R contained in the alkyl α-diazodiallylphosphonoacetate starting ...
