Sc(OTf)3-Catalyzed Diastereoselective Hydroxyheteroarylation of C–C σ-Bonds of Bicyclo[1.1.0]butanes with Azaheterocyclic N-Oxides

A mild and atom-economical reaction for the Sc(OTf)₃-catalyzed 1,3-hydroxyheteroarylation of bicyclo[1.1.0]butanes (BCBs) with azaaryl N-oxides via an unprecedented [4π+2σ] cycloaddition/ring-opening process is described. This transformation provides a novel strategy for the highly regio- and diastereoselective preparation of azaheterocycle-tethered 1,1,3,3-tetrasubstituted cyclobutane derivatives and offers a broad substrate scope and high yields.