1,2-Sulfanyl Group Migration as a Driving Force: New Approach to Pyrroles by Reaction of Allenic Aldehydes with Amines
摘要:
Acid-promoted reaction of sulfanyl group substituted allenic aldehyde with amine affords pyrrole derivatives in high yields. The neighboring group participation of the sulfanyl group is the driving force in this transformation.
Copper-catalyzed Pummerer type reaction of α -thio aryl/heteroarylacetates: Synthesis of aryl/heteroaryl α -keto esters
作者:Pipas Saha、Sumit Kumar Ray、Vinod K. Singh
DOI:10.1016/j.tetlet.2017.03.069
日期:2017.5
A copper catalyzed Pummerer type reaction of α-thio aryl/heteroarylacetates is described for the first time. This transformation represents a new route to synthesize α-keto esters, which are important intermediates for pharmaceuticals and organic synthesis. The reaction proceeds via in situ generation of a thionium ion that undergoes hydrolysis to furnish α-keto esters in synthetically viable yields
Catalytic O–H bond insertion reactions using surface modified sewage sludge as a catalyst
作者:Zhipeng Zhang、Yang Yu、Fei Huang、Xiangyan Yi、Yao Xu、Yide He、Jonathan B. Baell、He Huang
DOI:10.1039/c9gc03428e
日期:——
More economically and greener surface modified sewage sludge for carbene insertion of diazo compounds into O–H bond of phenols with good yields and high functional group tolerance.
将废水污泥进行经济和环保的表面改性,以较高产率和较高官能团耐受性将重氮化合物插入酚的O-H键。
Photochemical, Metal‐Free Sigmatropic Rearrangement Reactions of Sulfur Ylides
作者:Zhen Yang、Yujing Guo、Rene M. Koenigs
DOI:10.1002/chem.201900597
日期:2019.5.10
Sigmatropic rearrangement reactions constitute one of the most fundamental reactions of carbenes. While state‐of‐the‐art synthetic methods require the use of expensive precious metal catalysts, the application of visible light for the photolysis of α‐aryldiazoacetates is much less investigated and provides an operationally simple entry to carbenes under mild reaction conditions. Herein, we report on
Catalyst-Free [2,3]-Sigmatropic Rearrangement Reactions of Photochemically Generated Ammonium Ylides
作者:Fang Li、Feifei He、Rene M. Koenigs
DOI:10.1055/s-0037-1610732
日期:2019.12
rearrangement reaction of ammoniumylides furnishes valuable α,α-disubstituted amino esters. In this work, we describe the visible-light photolysis reaction of aryldiazoacetates in the presence of tertiary amines that react via a free ammoniumylide in a sigmatropic rearrangement reaction to provide amino esters in moderate to very good yields (33 examples, up to 97% yield). The rearrangement reaction of ammonium
Copper‐Catalyzed Chemo‐ and Diastereoselective 1,3‐Dipolar Cycloaddition of Carbonyl Ylide and Aldehyde‐Tethered‐Cyclohexadienone to Access Polycyclic Systems
作者:Shiyong Peng、Hong Zhang、Yuqi Zhu、Ting Zhou、Jieyin He、Nuan Chen、Ming Lang、Hongguang Li、Jian Wang
DOI:10.1002/adsc.202100648
日期:2021.10.5
A copper-catalyzed tandem intermolecular ylide formation/intramolecular cycloaddition of diazo compounds and aldehyde-tethered-cyclohexadienones was reported, chemo- and diastereoselectively providing oxapolycyclic frameworks in moderate to excellent yields under mild conditions. This reaction creates two C−C bonds and one C−O bond with five stereocentres including two all-carbon quaternary centres