Stereoselective Formation of Linear AZA-Triquinanes by Three Consecutive Radical Ring Closures

Treatment of the trienyl N-chloroamine 5 with titanium trichloride affords regio- and stereoselectively, as the major product (nearly half of the overall yield) the 8-aza-4-anti-chloromethyl-cis, syn, cis tricyclo (6, 3, 0, 0 2,6) undecane 10d by serial homolytic cyclisations.