Synthesis of 2-Alkynoates by Palladium(II)-Catalyzed Oxidative Carbonylation of Terminal Alkynes and Alcohols
作者:Qun Cao、N. Louise Hughes、Mark J. Muldoon
DOI:10.1002/chem.201602558
日期:2016.8.16
PdII catalyst, utilizing a simple and inexpensive amine ligand (TMEDA), allows 2‐alkynoates to be prepared in high yields by an oxidativecarbonylation of terminal alkynes and alcohols. The catalyst system overcomes many of the limitations of previous palladiumcarbonylation catalysts. It has an increased substrate scope, avoids large excesses of alcohol substrate and uses a desirable solvent. The catalyst
Iron(III)-catalyzed direct synthesis of diphenylmethyl esters from 2-diphenylmethoxypyridine
作者:Van Hieu Tran、Minh Thanh La、Hee-Kwon Kim
DOI:10.1080/00397911.2019.1625063
日期:2019.9.17
has been developed for the synthesis of diphenylmethyl (DPM) esters from 2-diphenylmethoxypyridine. Various carboxylic acids readily reacted with 2-diphenylmethoxypyridine in the presence of FeCl3 as a catalyst to provide the desired DPM esters with high yields. The procedure is facile and enables effective synthesis of a variety of esters for the protection of carboxylic acids. Graphical Abstract
The carboxylative coupling of aryl/alkyl terminalalkynes, CO2 and benzyl halides was investigated using silver iodide as the catalyst and Cs2CO3 as the base in CH3CN under ligand-free conditions. This reaction protocol shows a wide substrate scope and high functional group tolerance ability for benzyl halides, in which various functionalized benzyl 2-alkynoates were achieved in good yields. This one-pot
芳基/烷基末端炔烃,CO的carboxylative耦合2使用碘化银作为催化剂和Cs和苄基卤化物进行了研究2 CO 3在CH基座3无配体的条件下,CN。该反应方案显示出宽的底物范围和对苄基卤的高官能团耐受能力,其中以良好的产率获得了各种官能化的2-炔基苄基酯。这种一锅,无配体和CH 3 CN介导的反应被证明易于处理,并且在大气CO 2压力下可以促进。
Convenient Formation of Diphenylmethyl Esters Using Diphenylmethyl Trichloroacetimidate
Diphenylmethyl trichloroacetimidate is a useful reagent for the protection of carboxylic acids as their corresponding diphenylmethyl esters. These esterifications proceed rapidly without the need for an added catalyst or promoter. A variety of carboxylic acid substrates undergo esterification in excellent yields with the trichloroacetimidate reagent, including substrates possessing acid- or base-sensitive functionality. Protection of a carboxylic acid with a highly enolizable alpha-stereocenter using diphenylmethyl imidate was also accomplished without racemization.