Lewis Acid Catalyzed Dual Strain-Release Platform for Transforming Azabicyclo[1.1.0]butanes into Functionalized Azetidines with Donor–Acceptor(D-A) Cyclopropanes and Bicyclo[1.1.0]butanes

Herein, we disclose a catalytic dual strain-release approach that achieves orthogonal N1 and C3 functionalization of azabicyclo[1.1.0]butanes (ABBs) through synergistic engagement with donor-acceptor cyclopropanes (DACs). Orthogonal Lewis acid polarization of the cyclopropane relays activation to ABB, permitting access to functionalized azetidines, through cleavage of the strained C-N bond of ABB. Extending this activation paradigm to bicyclo[1.1.0]butanes (BCBs) further demonstrates the generality of this concept.