nanoparticles efficiently catalyzed the C–S cross coupling of aryl and alkyl thiols with aryl halides in the absence of ligands on water under mild conditions. A wide range of diaryl sulfides and aryl alkyl sulfides are synthesized in good to excellent yields utilizing this protocol. This procedure is particularly noteworthy given its mild conditions, avoiding the undesired formation of disulfides through
Chemo-Controlled Cross-Coupling of Di(hetero)aryl Disulfides with Grignard Reagents: CC<i>vs.</i>CS Bond Formation
作者:Bao-Xin Du、Zheng-Jun Quan、Yu-Xia Da、Zhang Zhang、Xi-Cun Wang
DOI:10.1002/adsc.201400980
日期:2015.4.13
A general protocol for the chemoselectivity‐controlled CC and CS coupling reactions of di(hetero)aryldisulfides with Grignardreagents catalyzed by ferrocene and palladium acetate has been developed. Ferrocene favored the formation of CS coupled products at low temperature, whereas CCbond couplings were favored when palladium acetate was used. All the reactions proceeded with excellent chemoselectivity
A facile preparation method for α,α-difluoroalkanecarboxylic acids and esters. A formal difluoromethylene insertion to alkanecarboxylic acids using radical reaction
the photoreaction of a series of Barton esters reacted with 1,1-dichloro-2,2-difluoroethene to give radical adducts as the major product accompanied with self-trapping products. Primary, secondary, tertiary, benzyl, and some unsaturated alkyl radicals as well as those with another functional group such as ether, carbonyl, and azide were applicable. Barton esters of diacids also afford 1:2 adducts with
通过一系列Barton酯的光反应生成的各种烷基自由基与1,1-二氯-2,2-二氟乙烯反应,生成自由基加合物作为主要产物,并伴有自捕获产物。伯,仲,叔,苄基和一些不饱和烷基以及具有另一官能团的那些如醚,羰基和叠氮化物是适用的。二元酸的巴顿酯还可以提供1:2加合物,以及少量的1:1加合物和双自陷产物(琥珀色情况除外)。这些加合物用AgNO 3 / H 2 O-THF水解为α,α-二氟链烷羧酸,并用AgNO 3甲醇水解。用/ MeOH制得相应的甲酯。将4-叠氮基-2,2-二氟丁酸和甲酯转化为二氟-GABA和二氟-γ-内酰胺。
α,α-Difluroalkanecarboxylic acids: a general synthesis via alkyl radical addition to 1,1-dichloro-2,2-difluoroethylene
Photodecomposition of alkanoic acid esters of N-hydroxy-2-thiopyridone with 1,1-dichloro-2,2-difuoroethylene gives alkyl-radical-trapped products, which give α,α-difluroalkanoic acids and their methyl esters on hydrolytic or methanolytic treatment with silver nitrate.