Modular Route to Azaindanes.

A convergent radical based route to azaindanes is described, relying on the degenerative addition transfer of various substituted S-(pyridylmethyl)-O-ethyl dithiocarbonates (xanthates) to functional alkenes followed by radical cyclization onto the pyridine ring activated by protonation with trifluoroacetic acid. In one case, a richly decorated cyclohepta[b]pyridine could be assembled swiftly by allowing the first adduct to N-phenylmaleimide to undergo addition to N-allylphthalimide prior to cyclization.