Carbonylation reactions represent useful tools for organic synthesis. However, the necessity to use gaseous carbon monoxide is a disadvantage for most organic chemists. To solve this problem, novel protocols have been developed for conducting palladium‐catalyzed reductive carbonylations of arylbromides and alkoxycarbonylations using paraformaldehyde as an external CO source (CO gas free). Hence, aromatic
Metal-free radical aromatic carbonylations mediated by weak bases
作者:Denis Koziakov、Axel Jacobi von Wangelin
DOI:10.1039/c7ob01572k
日期:——
We report a new method of metal-free alkoxycarbonylation. This reaction involves the generation of aryl radicals from arenediazonium salts by a very weak base (HCO2Na) under mild conditions. Subsequent radical trapping with carbon monoxide and alcohols gives alkyl benzoates. The conditions (metal-free, 1 equiv. base, MeCN, r.t., 3 h) tolerate various functional groups (I, Br, Cl, CF3, SF5, NO2, ester)
Trideuteromethylation Enabled by a Sulfoxonium Metathesis Reaction
作者:Zuyuan Shen、Shilei Zhang、Huihui Geng、Jiarui Wang、Xinyu Zhang、Anqi Zhou、Cheng Yao、Xiaobei Chen、Wei Wang
DOI:10.1021/acs.orglett.8b03641
日期:2019.1.18
A conceptually novel sulfoxonium metathesisreaction between TMSOI and cost-effective DMSO-d6 is developed for the efficient generation of a new trideuteromethylation reagent TDMSOI. The new reagent TDMSOI is produced highly efficiently by simply heating a mixture of TMSOI and DMSO-d6 and directly used for subsequent trideuteromethylation in a “one-pot” operation. The preparative power of the new versatile
TMSOI 和经济高效的 DMSO- d 6之间的概念上新颖的硫鎓复分解反应被开发出来,用于有效生成新型三氘代甲基化试剂 TDMSOI。新试剂TDMSOI只需加热TMSOI和DMSO- d 6的混合物即可高效生产,并直接用于后续的“一锅”操作中的三氘代甲基化。新的多功能试剂和“一锅”方案的制备能力通过其以高产率和有用的方式将-CD 3部分安装到广泛的功能中而得到证明,包括苯酚、苯硫酚、酸性胺和烯醇化亚甲基单元。氘化水平 (>87% D)。
Ligand-Promoted Nickel-Catalyzed <i>para</i>-Selective Carboxylation of Anisoles
10-phenanthroline with nickel(II) as the catalyst. A wide variety of anisoles were compatible, leading to para-carboxylated products in moderate to good yields. A preliminary mechanistic study suggested that the Ni(II) complex coordinates with the methoxyl group of the aromatic ring, which may have increased the steric hindrance at the ortho and meta positions, while this weak interaction reduces the aromaticity
Copper-Catalyzed O-Methylation of Carboxylic Acids Using DMSO as a Methyl Source
作者:Can-Cheng Guo、Jing Jia、Qing Jiang、An Zhao、Bin Xu、Qiang Liu、Wei-Ping Luo
DOI:10.1055/s-0035-1560967
日期:——
Abstract A copper-catalyzed O-methylation of carboxylic acidsusing dimethyl sulfoxide (DMSO) as the methyl source is disclosed. This transformation exhibits a broad substrate scope and excellent functional group tolerance. Mechanistic studies indicate that a methyl radical is generated from dimethyl sulfoxide in the reaction process. A copper-catalyzed O-methylation of carboxylic acidsusing dimethyl