stereoconvergent 1,3-dipolar cycloaddition of nitrileoxides and nitrile imines with E/Z isomeric mixture of electron-deficient olefins is reported, delivering isoxazolines and pyrazolines bearing two vicinal stereogenic tertiary and trifluoromethylated quaternary carbon centers with perfect regio- and diastereoselectivities. The possibility of concerted cycloaddition/epimerization sequence under basic
practical protocol for the synthesis of fully substituted pyrazoles from pyridinium 1,4-zwitterionic thiolates and hydrazonoyl chlorides in excellent yields under mild conditions is described. The transformation proceeds via an unusual [[3 + 3] - 1] pathway, which involves a formal [3 + 3] cascade cyclization followed by a spontaneous ring-contraction/sulfur extrusion reactionfrom 4H-1,3,4-thiadiazine intermediates
A novel sequential [3+2] annulation reaction has been developed using prop-2-ynylsulfonium salts and hydrazonyl chlorides, affording a series of pyrazoles with functional motifs that can be post modified in the preparation of various drugs or drug candidates. Further transformation and gram-scale operations could also be achieved efficiently.
A silver-catalyzed one-pot cycloisomerization/[2 + 3] cycloaddition of enynamides with in situ generated nitrile imines has been developed. Unlike the well-established cycloisomerization/[4 + n] cycloadditions of enynamides, this strategy provides efficient access to a new type of spiropyrazolines, which exhibit an anti-proliferation effect on multiple tumor cell lines. The compound 3u exhibits obvious
开发了一种银催化的烯炔酰胺与原位生成的腈亚胺的一锅环异构化/[2+3]环加成反应。与成熟的烯炔酰胺环异构化/[4 + n ]环加成不同,该策略提供了有效获得新型螺吡唑啉的途径,该螺吡唑啉对多种肿瘤细胞系表现出抗增殖作用。化合物3u通过诱导RKO细胞凋亡而表现出明显的抗癌活性。化合物3u与自噬抑制剂的组合可以提高其抗增殖能力。
Regioselective synthesis of spiro naphthofuranone-pyrazoline via a [3+2] cycloaddition of benzoaurones with nitrile imines
作者:Yingpeng Su、Chenglong Ma、Yanan Zhao、Caixia Yang、Yawei Feng、Ke-Hu Wang、Danfeng Huang、Congde Huo、Yulai Hu