Rhodium(I)-Catalyzed Cycloisomerizations of Bicyclobutanes

The selection of rhodium precatalyst and phosphine ligand determines the course of the cycloisomerization of N-allylated bicyclo[1.1.0]butylalkylamines. Cyclopropane-fused pyrrolidines and azepines are obtained with high levels of stereo- and regiocontrol. Novel azatricyclo[6.1.0.01,5]nonanes are the result of a tandem cycloisomerization−ring closing metathesis sequence. Allylic ethers lead to furans and oxepanes.