... Materials.-1,l'-Azobisformamide (ABFA) (Aldrich Chem- ical Co.) [A:$' (emsx) 262 (1680), 423 (5l.l)], azobenzene (East- man Organic Chemicals), and benzoyl peroxide (Lucidol Division of ... Chem. Soc., 91, 3655 M. J. S. Dewar and W. B. Jennlngs, Tetrahedron Lett., 339 (19701, ...