100782-33-0Relevant academic research and scientific papers
Chemistry of amido radicals: intramolecular hydrogen abstraction as related to amido radical configurations
Chow, Yuan L.,Mojelsky, Thomas W.,Magdzinski, Leon J.,Tichy, M.
, p. 2197 - 2202 (2007/10/02)
Model bromamides were photolysed to investigate the reactivity of intramolecular C-5 hidrogen abstraction (from the nitrogen atom) of the corresponding amidyl radicals and of the cyclization of the resulting C-bromides.The observed results are discussed in terms of stereoelectronic as well as energetic considerations.In the former C-5 hydrogen abstraction, the reactivity difference between semi-rigid trans and cis-oriented reaction centers is only slightly in favor of the latter; the small difference is interpreted as due to the planar ground state Π amidyl radical structure with a low N-CO twisting barrier (4-5 kcal/mol).This interpretation is supported by the efficient C-5 hydrogen abstraction in N-bromo-N-alkyltoluamides, since a rigid planar amidyl radical does not allow the methyl C-H bond to colinearly approach the Π orbital.In marked contrast, there are large reactivity differences in the cyclization of C-bromides derived from these intramolecular H-Br exchanges; these arise from the requirement of colinearity of the approaching and departing bonds.Thus this requries the coplanar orientation of the C-CH3 and C-CO bonds and this is the source of the reactivity differences.
