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The polarity reversal (umpolung) reaction is an invaluable tool for reversing the chemical reactivity of carbonyl and iminyl groups, which subsequent cross‐coupling reactions to form C−C bonds offers a unique perspective in synthetic planning and implementation. Reported herein is the first visible‐light‐induced polarity‐reversed allylation and intermolecular Michael addition reaction of aldehydes, ketones, and imines. This chemoselective reaction has broad substrate scope and the engagement of alkyl imines is reported for the first time. The mechanistic investigations indicate the formation of ketyl (or α‐aminoalkyl) radicals from single‐electron reduction, where the Hantzsch ester is crucial as the electron/proton donor and the activator. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(45):14352-14356
Described herein is a selective way to control the reaction of allylic amines with metalorganic bases depending on the amine handle as well as the metalorganic base is used. Depending on the number of coordinating groups within the amine handle either a selective carbometalation or deprotonation reaction can be performed. By changing the alkali metal within the base from lithium to either sodium or potassium, a change of chemoselectivity takes place and the reaction of piperidinoallylamine can be controlled. 相似文献
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Zhong‐Lin Tao Alafate Adili Hong‐Cheng Shen Zhi‐Yong Han Liu‐Zhu Gong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(13):4394-4398
A highly selective multicomponent carbonyl allylation reaction of 1,3‐butadienes, aryldiazonium tetrafluoroborates, and aldehydes has been established under the combined catalysis of palladium acetate and chiral anion phase transfer to render the favorable assembly of chiral Z‐configured homoallylic alcohols in high yields and with excellent levels of enantioselectivity. 相似文献
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