证明了烯烃与苯甲基烃的催化加氢烷基化反应涉及t -BuOK/DMF 介导的苯甲基 C-H 键活化。这种直接且操作简单的方案可以快速、可靠地获得各种苄基化合物,且产率从良好到优异。活化二芳基甲烷(p K a ∼ 32.2)和苄基硫醚(p K a ∼ 30.8)或惰性烷基苯的苄基C-H都可以作为有用的合成平台,在温和的反应条件下方便地烷基化。
Organocatalytic decarboxylative alkylation of <i>N</i>-hydroxy-phthalimide esters enabled by pyridine-boryl radicals
作者:Liuzhou Gao、Guoqiang Wang、Jia Cao、Dandan Yuan、Cheng Xu、Xuewen Guo、Shuhua Li
DOI:10.1039/c8cc06152a
日期:——
The decarboxylative alkylation of N-hydroxyphthalimide (NHPI) based reactive esters with olefins has been achieved via an organocatalytic strategy. Control experiments and density functional theory calculations suggest that these reactions involve a boryl-radical mediated decarboxylation pathway, which is different from the single electron transfer involved in decarboxylative alkylation reactions reported
for the synthesis of diarylmethine‐containing compounds. However, the methods developed to date for this purpose require a stoichiometric amount (usually more) of either a strong base or an oxidant. Reported here is the first catalytic benzylic C−H bond addition of diarylmethanes to styrenes and conjugated dienes. A potassium zincate complex, generated from potassium benzyl and zinc amide, acts as
Substituted Hantzsch esters can act as radical reservoirs in photoredox reactions, steadily releasing a carbon radical and a hydrogen atom radical in the absence of an additional electron acceptor. We propose that radical release by substituted Hantzsch esters occurs via a mechanism involving an internal redox cycle. Cinnamidecinnamides, styrenes, α,β‐unsaturated acids, and diarylethenes could be alkylated
Oxo-Rhenium-Catalyzed Radical Addition of Benzylic Alcohols to Olefins
作者:Chandrasekhar Bandari、Kenneth M. Nicholas
DOI:10.1021/acs.joc.9b03150
日期:2020.3.6
Although carbon radicals generated from a variety of alcohol derivatives have proven valuable in coupling and addition reactions, the direct use of alcohols as synthetically useful radical sources is less known. In this report, benzylic alcohols are shown to be effective radical precursors for addition reactions to alkenes when treated with triphenylphosphine or piperidine with the catalyst ReIO2(PPh3)2 (I)
Continuous Flow Preparation of Benzylic Sodium Organometallics
作者:Johannes H. Harenberg、Rajasekar Reddy Annapureddy、Konstantin Karaghiosoff、Paul Knochel
DOI:10.1002/anie.202203807
日期:2022.7.25
A lateral sodiation of alkyl(hetero)arenes using on-demand generated (2-ethylhexyl)sodium in the presence of TMEDA is reported. Various electrophiles were used for trapping of the benzyl sodium species generated in continuous flow as well as in batch. The continuous flow metalation was scaled-up using an in-line quench. The method was used in the synthesis of several industrial relevant compounds.