Li Xiang, Zhou Bo, Yang Run-Ze, Yang Fu-Ming, Liang Ren-Xiao, Liu Ren-Rong, Jia Yi-Xia
College of Chemical Engineering, State Key Laboratory Breeding Base of Green-Chemical Synthesis Technology , Zhejiang University of Technology , Chaowang Road 18# , Hangzhou 310014 , China.
J Am Chem Soc. 2018 Oct 24;140(42):13945-13951. doi: 10.1021/jacs.8b09186. Epub 2018 Oct 10.
Enantioselective intramolecular dearomative Heck reactions have been developed by Pd-catalyzed cross-coupling of aryl halides or aryl triflates with the internal C═C bond of indoles, benzofurans, pyrroles, and furans. A variety of structurally unique spiroheterocycles and benzofused heterocycles having N/O-substituted quaternary carbon stereocenters, and exocyclic olefin moieties were afforded in moderate to excellent yields with good to excellent enantioselectivities, showing a broad scope of the present protocol. A series of new BINOL- and H8-BINOL-based phosphoramidite ligands were synthesized and proved to be efficient chiral ligands in the reactions of C2-tethered substrates to form spiroheterocycles. ( S)-SEGPHOS turned out to be a good ligand for the reaction delivering benzofused indolines and pyrrolines. Synthetic applications based on transformations of the exocyclic double bonds were realized without loss of enantiopurities, including hydrogenation, hydroborylation, and stereospecific ring-expanding rearrangement.
通过钯催化芳基卤化物或芳基三氟甲磺酸酯与吲哚、苯并呋喃、吡咯和呋喃的内碳-碳双键的交叉偶联反应，已开发出对映选择性分子内去芳构化Heck反应。以中等至优异的产率和良好至优异的对映选择性得到了各种结构独特的具有N/O取代季碳立体中心的螺杂环和苯并稠合杂环，以及环外烯烃部分，表明本方法具有广泛的适用范围。合成了一系列基于新型联萘酚和H8-联萘酚的亚磷酰胺配体，并证明它们在C2连接底物形成螺杂环的反应中是有效的手性配体。（S）-SEGPHOS被证明是用于生成苯并稠合二氢吲哚和二氢吡咯反应的良好配体。基于环外双键转化的合成应用得以实现，且对映体纯度无损失，包括氢化、硼氢化和立体特异性扩环重排。
