Late‐stage synthesis of α,β‐unsaturated aryl ketones remains an unmet challenge in organic synthesis. Reported herein is a photocatalytic non‐chain‐radical aroyl chlorination of alkenes by a 1,3‐chlorine atom shift to form β‐chloroketones as masked enones that liberate the desired enones upon workup. This strategy suppresses side reactions of the enone products. The reaction tolerates a wide array
Conjugateaddition to 1,4-dicarbonylbut-2-enes will generate an α-stereogenic center with respect to one of the carbonyl groups, which informally, can be considered as an inversion of normal reactivity patterns or umpolung protocol. In this paper, the addition of tert-butyl mercaptan to 1,4-dicarbonylbut-2-enes including (E)-4-oxo-4-arylbutenamides and (E)-4-oxo-4-arylbutenones has been developed,
Asymmetric [4 + 2] annulation of 5H-thiazol-4-ones with a chiral dipeptide-based Brønsted base catalyst
作者:Bo Zhu、Shuai Qiu、Jiangtao Li、Michelle L. Coote、Richmond Lee、Zhiyong Jiang
DOI:10.1039/c6sc02039a
日期:——
we have developed a new family of dipeptide-based multifunctional Brønsted base organocatalysts that are highly capable of the first asymmetric [4 + 2] annulation reaction of 5H-thiazol-4-ones with electron-deficient alkenes. This protocol could be applied to a series of alkenes such as nitroalkenes, 4-oxo-4-arylbutenones, 4-oxo-4-arylbutenoates and methyleneindolinones, providing an efficient approach
Synthesis of α-Stereogenic Amides and Ketones by Enantioselective Conjugate Addition of 1,4-Dicarbonyl But-2-enes
作者:Zhiyong Jiang、Yuanyong Yang、Yuanhang Pan、Yujun Zhao、Hongjun Liu、Choon-Hong Tan
DOI:10.1002/chem.200802601
日期:2009.5.4
Constructing α‐stereogenic amides and ketones: The highly regioselective and enantioselectiveconjugateaddition of 1,3‐dicarbonyl compounds to 1,4‐dicarbonyl but‐2‐enes has been developed with the chiral bicyclic guanidine as catalyst (ee values up to 97 %; see scheme).
Aerobic Oxidative Dehydrogenation of Ketones to 1,4-Enediones
作者:Bao-Yin Zhao、Xing-Long Zhang、Rui-Li Guo、Meng-Yue Wang、Ya-Ru Gao、Yong-Qiang Wang
DOI:10.1021/acs.orglett.0c04174
日期:2021.2.19
An efficient and unprecedented strategy for the synthesis of 1,4-enediones from saturated ketones has been developed via palladium-catalyzedoxidativedehydrogenation. The protocol employs molecular oxygen as the sole oxidant and represents an atom- and step-economic process. The approach showed broad substrate scope, good functional group tolerance, and complete E-stereoselectivity. The reaction mechanism