A Novel, One-Pot Ring Expansion of Cyclobutanones. Syntheses of Carbovir and Aristeromycin

A novel, one-pot ring-expansion procedure was developed using Me₃S(O)I, NaH, and Sc(OTf)₃. The scope and limitations were briefly examined, and a tentative mechanism was proposed. Application of the methodology to known cyclobutanone 1 provided the corresponding cyclopentanone, which was successfully advanced to (+)-carbovir and (+)-aristeromycin.