Synthesis of β‐N‐Heterocyclic‐Cyclobutane‐Fused Bicyclic γ‐Lactones from 2‐Hydroxycyclobutanone and Carboxamide‐Bearing Wittig Reagents

A cascade reaction has been established that enables access to structurally diverse 2-oxabicyclo[3.2.0]heptan-3-ones bearing a benzo[d]oxazol-2(3H)-one moiety at the bridgehead quaternary center in moderate to good yields in a single operation. The reaction illustrates the potential of 2-hydroxycyclobutanone as a substrate for the rapid preparation of unusual and complex molecular frameworks.