P(NMe<sub>2</sub>)<sub>3</sub>-Mediated Reductive Intramolecular Annulation of Benzoylformates Tethered with a Trisubstituted Alkene Unit and Synthesis of 2,2-Disubstituted 2<i>H</i>-Chromenes
作者:Jiayong Zhang、Yuhe Qiu、Biao Zhang、Zhiqiang Huang、Zhengjie He
DOI:10.1021/acs.orglett.1c00286
日期:2021.3.5
report, a P(NMe2)3-mediated reductive intramolecular annulation reaction has been developed with benzoyl formates bearing a trisubstituted alkene unit. It provides a facile synthesis of highly functionalized 2,2-disubstituted 2H-chromenes with a broad substratescope and high efficiency. Experimental results suggest this annulation reaction proceeds via a cascade of alkene isomerization/vinyl o-quinone
P<sup>III</sup>-Mediated intramolecular cyclopropanation and metal-free synthesis of cyclopropane-fused heterocycles
作者:Jiayong Zhang、Jiahang Hao、Zhiqiang Huang、Jie Han、Zhengjie He
DOI:10.1039/d0cc04086j
日期:——
A P(NMe2)3-mediated reductive intramolecular cyclopropanation is developed for the first time, which provides facileaccess to a wide variety of cyclopropane-fused heterocycles including chromanes, tetrahydroquinolines, lactones, and lactams. Catalytic hydrogenative ring-expansion of the cyclopropane-fused heterocycles is also elaborated, leading to various structurally important medium-sized heterocycles
Synthesis of quaternary carbon centered chromans from the reactions of ethyl 2-(2-hydroxyaryl)-2-oxoacetates with allenic ester or allenic sulfone catalyzed by tertiary phosphine and SPTS
作者:Fangle Hu、Xiaoyang Guan、Min Shi
DOI:10.1016/j.tet.2012.04.036
日期:2012.6
Cyclization reactions of ethyl 2-(2-hydroxyaryl)-2-oxoacetates with ethyl 2,3-butadienoate and allenylsulfone proceeded smoothly in the presence of tertiary phosphine and sodium p-toluenesulfinate (SFTS) to give the corresponding quaternary carbon centered chromans in moderate to good yields under mild conditions, which provides an alternative efficient approach for the synthesis of biologically active chroman products. (C) 2012 Elsevier Ltd. All rights reserved.