132352-93-3Relevant articles and documents
ALKOXYNITRENIUM ION CYCLISATIONS: EVIDENCE FOR DIFFERENT MECHANISMS IN THE FORMATION OF BENZOXAZINES AND BENZOXAZEPINES.
Glover, Stephen A.,Rowbottom, Colleen A.,Scott, Anthony P.,Schoonraad, Johan L.
, p. 7247 - 7262 (2007/10/02)
Deuterium labelling experiments and n.m.r. studies indicate that cyclisations of N-acyl-N-(2-phenylethyloxy)nitrenium ions occur via direct attack at the ortho position to give 3,4-dihydro-1H-2,1-benzoxazines.In contrast N-acyl-N-(3-phenylpropyloxy)nitrenium ions cyclise to 1,3,4,5-tetrahydro-2,1-benzoxazepines through ipso attack followed by 1,2-carbon migration.In both cases hydrogen circumambulation occurs in the sigma complex before aromatisation.