Modular Synthesis\nof Azidobicyclo[2.1.1]hexanes via\n(3 + 2) Annulation of α‑Substituted Vinyl Azides and\nBicyclo[1.1.0]butanes

Here, we present a mild and rapid method to access azidobicyclo[2.1.1]hexanes\nvia formal (3 + 2) cycloaddition of α-substituted vinyl azides\nand bicyclo[1.1.0]butanes under Lewis acid catalysis. A wide range\nof α-substituted vinyl azides were tolerated under mild conditions.\nNotably, the resulting cycloadducts could be transformed into structurally\nattractive 3-azabicyclo[3.1.1]heptenes through microwave-promoted\nrearrangement. The utilities were highlighted by copper(I)-catalyzed\nHuisgen 1,3-dipolar cycloaddition of tertiary alkyl azide and further\ntransformation of the azide and ketone groups.