Phosphonite mediated 1,3-dipolar cycloaddition: a route to polycyclic 2-pyrrolines from imines, acid chlorides and alkenes.

2-Pyrrolines can be generated by the PhP(2-catechyl) mediated coupling of alkene-tethered imines and acid chlorides. This reaction proceeds via phosphorus-containing 1,3-dipoles, which undergo cycloaddition with alkenes with high stereo- and regioselectivity. The modularity of this reaction can be used to assemble a range of polysubstituted pyrrolines in one pot transformations.