developed, providing various chiral α-monosubstituted α-aminoacidderivatives with excellent results (97-99% yields, 90 to >99% ee). Cyclic N-sulfonyl ketimines were also hydrogenated well to afford chiral amine derivatives with 98-99% yields and 97 to >99% ee. The gram-scale asymmetric hydrogenation was performed well with 85% yield and 99% ee using only 0.2 mol% catalyst.
Phosphine-Catalyzed (4 + 1) Annulation of <i>o</i>-Hydroxyphenyl and <i>o</i>-Aminophenyl Ketones with Allylic Carbonates: Syntheses and Transformations of 3-Hydroxy-2,3-Disubstituted Dihydrobenzofurans and Indolines
作者:Zifeng Qin、Wei Liu、Danyang Wang、Zhengjie He
DOI:10.1021/acs.joc.6b00596
日期:2016.6.3
A phosphine-catalyzed (4 + 1) annulationreaction of o-hydroxyphenyl and o-aminophenyl ketones with ester-modified allylic carbonates has been developed, providing a facile and efficient method to synthesize functionalized 2,3-disubstituted dihydrobenzofurans and indolines. Under mild conditions and in the catalysis of PPh3 (20 mol %), the reactions of o-hydroxyphenyl or o-aminophenyl ketones readily
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
Lewis Base-Catalyzed Intramolecular Vinylogous Aldol Reaction and Chemoselective Syntheses of 3-Hydroxy-2,3-Disubstituted Dihydrobenzofurans and Indolines
作者:Jiayong Zhang、Zhengjie He
DOI:10.1021/acs.joc.3c01313
日期:2023.9.15
A Lewis base-catalyzed intramolecular vinylogous aldol reaction of o-(allyloxy)phenyl ketoesters or o-(allylamino)phenyl ketoesters has been developed. This reaction provides ready access to 3-hydroxy-2,3-disubstituted dihydrobenzofurans and indolines in high yields with excellent chemoselectivity and diastereoselectivity. An acid-promoted dehydration of such products further extends the utility of