Hu Jiefeng, Wang Guoqiang, Li Shuhua, Shi Zhuangzhi
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China.
Key Laboratory of Mesoscopic Chemistry of Ministry of Education, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China.
Angew Chem Int Ed Engl. 2018 Nov 12;57(46):15227-15231. doi: 10.1002/anie.201809608. Epub 2018 Oct 17.
An efficient method for the metal-free deaminative borylation of alkylamines, using bis(catecholato)diboron as the boron source, to directly synthesize various alkyl potassium trifluoroborate salts is introduced. The key to this high reactivity is the utilization of pyridinium salt activated alkylamines, with a catalytic amount of a bipyridine-type Lewis base as a promoter. This transformation shows good functional-group compatibility (e.g., it is unimpeded by the presence of a ketone, indole, internal alkene, or unactivated alkyl chloride) and can serve as a powerful synthetic tool for borylation of amine groups in complex compounds. Mechanistic experiments and computations suggest a mechanism in which the Lewis base activated B cat unit intercepts an alkyl radical generated by single-electron transfer (SET) from a boron-based reductant.
介绍了一种使用双（邻苯二酚）二硼作为硼源，对烷基胺进行无金属脱氨基硼化反应以直接合成各种烷基三氟硼酸钾盐的有效方法。这种高反应活性的关键在于利用吡啶盐活化的烷基胺，并以催化量的联吡啶型路易斯碱作为促进剂。该转化反应显示出良好的官能团兼容性（例如，酮、吲哚、内烯烃或未活化的烷基氯的存在不会对其产生阻碍），并且可作为复杂化合物中胺基硼化的有力合成工具。机理实验和计算表明了一种机理，即路易斯碱活化的B cat单元拦截由硼基还原剂通过单电子转移（SET）产生的烷基自由基。
