Treatment of N-(o-bromobenzyl)anilines with 1-3 equivalent amounts of
n-tributyltinhydride, in the presence of 0.5 to 0.6 mol equiv. of AIBN
, results in the formation of phenanthridines in good yields. The mech
anism of the oxidation step is probed with a deuterated aniline deriva
tive and azobiscyclohexylcarbanonitrile (ABCN) as the initiator. It is
shown that the carbon centred radical derived from the latter does no
t act as the hydrogen abstracting species. Copyright (C) 1996 Elsevier
Science Ltd