A novel method for the mild photoredox‐mediated tandem radical acylarylation and tandem acylation/semipinacol rearrangement has been developed. The synthesis of highly functionalized ketones bearing all‐carbon α‐ or β‐quaternary centers has been achieved using easily available symmetric aromatic carboxylic anhydrides as the acyl radical source. The method allows for a straightforward introduction of
Catalyst-Dependent Chemoselective Formal Insertion of Diazo Compounds into C−C or C−H Bonds of 1,3-Dicarbonyl Compounds
作者:Zhaohong Liu、Paramasivam Sivaguru、Giuseppe Zanoni、Edward A. Anderson、Xihe Bi
DOI:10.1002/anie.201802834
日期:2018.7.16
one‐carbon insertion of diazo compounds into the C−C or C−H bonds of 1,3‐dicarbonyl species is reported. In the presence of silver(I) triflate, diazo insertion into the C(=O)−C bond of the 1,3‐dicarbonyl substrate leads to a 1,4‐dicarbonyl product containing an all‐carbon α‐quaternary center. This reaction constitutes the first example of an insertion of diazo‐derived carbenoids into acyclic C−C bonds. When
Direct incorporation of two carbonyl groups into a double bond by diacylation is achieved for the first time via visible-light catalysis. Key to success is that N(n-Bu)4+ not only associates with the alkyl anion to avoid protonation, but also activates the α-keto acid to undergo electrophilic addition. The metal-free, redox-neutral and regioselective symmetric and unsymmetric 1,2-dicarbonylation of
通过可见光催化,首次实现了通过二酰化将两个羰基直接结合到双键中。成功的关键是 N( n -Bu) 4 +不仅与烷基阴离子缔合以避免质子化,而且还激活α-酮酸进行亲电加成。烯烃的无金属、氧化还原中性和区域选择性对称和不对称 1,2-二羰基化具有许多应用的潜力。