Development of a New Catalytic System for the Carbon Radical Generation and Its Application to Organic Syntheses.

实现碳氢化合物高效和选择性地转化为有用的化学物质是合成化学中一个雄心勃勃的目标。利用N-羟基邻苯二甲酰亚胺(NHPI)作为碳自由基生成催化剂(CRPC)，开辟了有机合成的新前景，确定了多种化合物的C-H键生成碳自由基的催化方法。以NHPI为催化剂，在温和的条件下实现了一种新型的烷烃好氧氧化反应，其转化率和选择性均优于传统的自氧化反应。这种氧化方法提供了一系列重要的含氧化合物的入口。特别是，环己烷在氧气中高转化率和高选择性地直接转化为己二酸的成功极大地有利于化学工业这一环境友好的过程，因为目前通过硝酸氧化生产己二酸导致了氮氧化物的释放，而氮氧化物是严重的空气污染物质。此外，NHPI还催化烷基苯类的有氧氧化，从而有效地合成了各种羧酸。己内酯和己内酰胺前体是由KA油生成α-羟基过氧化物制得的，不产生任何废物。这一新方法适用于烷烃与NO2反应生成硝基烷烃的官能化反应。最后，建立了烷烃与O2同时引入到烯烃中的一种新的反应类型--烯烃催化氧烷基化反应。α-羟基-γ-内酯是一种很难用常规方法合成的内酯，在NHPI催化剂的作用下，醇、烯烃和O2可以很容易地反应得到。NHPI可作为烯烃与醛氢酰化反应的极性反转催化剂。

The achievement of highly efficient and selective transformations of hydrocarbons to useful chemical substances is an ambitious goal in synthetic chemistry. It is interesting to open up a new vista in organic synthesis and to confirm the catalytic method for the carbon radical generation from a C-H bond of a wide variety of compounds by the use of N-hydroxyphthalimide (NHPI) which serves as a carbon radical producing catalyst (CRPC). By employing NHPI as the catalyst, a novel aerobic oxidation of alkanes, which surpasses the conventional autoxidations in conversion and selectivity, has been achieved under mild conditions. This oxidation method provides entry to a diverse array of significant oxygen-containing compounds. In particular, a success in the direct conversion of cyclohexane to adipic acid with dioxygen in high conversion and selectivity has greatly benefited the chemical industry as an environmentally benign process, because the current production of adipic acid via nitric acid oxidation causes the evolution of nitrogen oxides that are serious air-polluting materials. In addition, the NHPI catalyzes the aerobic oxidation of alkylbenzenes, thus various carboxylic acids were efficiently synthesized by this method. Caprolactone and caprolactam precursors were obtained through generation of alpha-hydroxyperoxides from KA-oil without formation of any wastes. This new methodology is applicable to the functionalization of alkanes to afford nitroalkanes by allowing them to react with NO_2. Finally, a new type of reaction for the concomitant introduction of alkanes and O_2 to alkenes, which is referred to as catalytic oxyalkylation of alkenes, has been established. α-Hydroxy-γ-lactones, which are very difficult to synthesize by conventional methods, are easily prepared by the reaction of alcohols, alkenes and O_2 under the influence of the NHPI catalyst. The NHPI can be used as a polarity-reversal catalyst for hydroacylation of alkenes with aldehydes.