Substituent‐Controlled Divergent Cascade Cycloaddition Reactions of Chalcones and Arylalkynols: Access to Spiroketals and
<i>Oxa</i>
‐Bridged Fused Heterocycles
作者:Tianlong Zeng、Jingyang Kong、Hongkai Wang、Lingyan Liu、Weixing Chang、Jing Li
DOI:10.1002/adsc.202100523
日期:2021.8.13
Herein, we report substituent-controlled divergentcascadecycloadditionreactions of chalcones and arylalkynols in the presence of PtI2. Depending on the substituent on the chalcone, either spiroketals or oxa-bridged fusedheterocycles could be obtained in the ranges of 86–97% and 87–95% yields under identical reaction conditions. Control experiments were carried out to elucidate the origin of the
Klages; Tetzner, Chemische Berichte, 1902, vol. 35, p. 3970
作者:Klages、Tetzner
DOI:——
日期:——
Enantioselective synthesis of 2-amino-4H-pyrans via the organocatalytic cascade reaction of malononitrile and α-substituted chalcones
作者:Zhi-Peng Hu、Wei-Juan Wang、Xiao-Gang Yin、Xue-Jing Zhang、Ming Yan
DOI:10.1016/j.tetasy.2012.03.018
日期:2012.4
An organocatalytic cascade reaction of malononitrile and a-substituted chalcones has been developed for the synthesis of chiral multisubstituted 2-amino-4H-pyran derivatives. A series of chiral primary/tertiary amines and cinchona alkaloids were examined as the catalysts. Quinine was found to be the most efficient catalyst in the absence of any additive. The alpha-substitutents of the chalcones had a siginificant effect on the yield and the enantioselectivity. A number of multisubstituted 2-amino-4H-pyrans were obtained in excellent yields and enantioselectivities. (C) 2012 Elsevier Ltd. All rights reserved.
Ru-catalyzed asymmetric hydrogenation of α,β-unsaturated ketones <i>via</i> a hydrogenation/isomerization cascade
作者:Kun Wang、Saisai Niu、Weijun Tang、Dong Xue、Jianliang Xiao、Hongfeng Li、Chao Wang
DOI:10.1039/d4cc00356j
日期:2024.4.16
Ru-catalyzed asymmetric hydrogenation of α-substituted α,β-unsaturatedketones has been developed for the enantioselective synthesis of chiral α-substituted secondary alcohols with high diastereo- and enantioselectivities (up to >99 : 1 dr, 98% ee). Mechanistic experiments suggest that the reaction proceeds via a Ru-catalyzed asymmetric hydrogenation of the CO bond in concert with a base-promoted allylic