Thermolyses of <i>O</i>-Phenyl Oxime Ethers. A New Source of Iminyl Radicals and a New Source of Aryloxyl Radicals
作者:Jessie A. Blake、Derek A. Pratt、Shuqiong Lin、John C. Walton、Peter Mulder、K. U. Ingold
DOI:10.1021/jo049927y
日期:2004.4.1
dissociation enthalpies, BDEs, and represent the first thermochemical data for any reaction yielding iminyl radicals. The small range in k (N−O homolyses) is consistent with the known σ structure of these radicals, and the variations in k and N−O BDEs with changes in RR‘ are rationalized in terms of iminyl radical stabilization by hyperconjugation: RR‘CN• ↔ R•R‘C⋮N. Calculated N−H BDEs in the corresponding RR‘CNH
六ø -苯基酮肟醚,RR'C挪弗1 - 6,与RR” =碳酸二芳基,二烷基,和芳基烷基,连同Ñ -phenoxybenzimidic酸苯基醚,的PhO(PH)C挪弗,7,已显示出在thermolyze具有“清洁” N-O键的适中温度会均一化,生成亚氨基和苯氧基,RR'C N •和PhO •。由于1 - 6可以在室温下进行合成,这些化合物提供iminyls的用于合成新的和潜在有用的源。该亚氨基从7所经历β-断裂之间的竞争,PHCN和的PhO •并环化成恶唑。速率常数,10 6 ķ /秒- 1,在90℃下为1 - 6范围从4.2(RR '= 9-芴基)〜180(RR'= 9- bicyclononanyl),并且对于7为0.61。估计的N-O键断裂的活化焓与N-O键离解焓BDE的DFT计算结果令人满意,并且代表了产生亚氨基自由基的任何反应的第一个热化学数据。k的小范围(N-O均溶)与这些基团的