Tributylstibine is an efficient reagent for debromination of phenacyl and arylmethyl bromides. The mechanistic difference between stibine and phosphine is discussed briefly.
A simple, cost-effective method for deuteration of carbonyl compounds employing pyrrolidine as catalyst and D2O as deuterium source was described. High degree of deuterium incorporation (up to 99%) and extensive functional group tolerance were achieved. It is the first time that secondary amines are used as catalysts for H/D exchange of carbonyl compounds, which also allow the deuteration of complex pharmaceutically interesting substrates. A possible catalytic mechanism, based on the hydrolysis of 1-pyrrolidino-1-cyclohexene, for this pyrrolidine-catalyzed H/D exchange reaction has been proposed.
Cobaloxime-catalyzed hydration of terminal alkynes without acidic promoters
作者:Shengtai Hou、Hongjian Yang、Bin Cheng、Hongbin Zhai、Yun Li
DOI:10.1039/c7cc03919k
日期:——
Cobaloxime (Co(dmgBF2)2·2H2O), an inexpensive first-row transition-metal complex, catalyzedhydration of terminalalkynes gave the corresponding methyl ketones in good to excellent yields under neutral conditions (additional protic acids and silver salts are not required). A wide range of functional groups, such as allyl ether, benzyl ethers, carboxylic esters, imides, amides, nitro, and halogens,
作者:Marcileia Zanatta、Francisco P. dos Santos、Cristina Biehl、Graciane Marin、Gunter Ebeling、Paulo A. Netz、Jairton Dupont
DOI:10.1021/acs.joc.6b03029
日期:2017.3.3
for the H/Dexchange reaction of various substrates using CDCl3 as D source, without the addition of any extra bases or metal. High deuterium incorporation (up to 49%) in acidic C–H bonds of ketone and alkyne substrates (pKa from 18.7 to 28.8) was found at room temperature. The reaction proceeds through the fast and reversible deuteration of the 2-methyl H of the imidazolium cation followed by D transfer
与碱性阴离子(例如碳酸氢盐,脯氨酸盐和咪唑酸盐)缔合的简单1,2,3-三烷基咪唑鎓阳离子是使用CDCl 3作为D源进行各种底物H / D交换反应的活性催化剂,而无需添加任何多余的碱或金属。酮和炔烃底物的酸性C–H键中氘的高掺入量(最高49%)(p K a在室温下发现(从18.7到28.8)。反应通过咪唑鎓阳离子的2-甲基H的快速可逆氘化进行,然后D转移至底物。IL充当中性碱催化剂,其中在反应过程中保持接触离子对。碱性活性位点归因于阴离子中存在一个偏远的碱性位点,即碳酸氢根的OH,脯氨酸根的NH和咪唑基阴离子中的活化水。详细的动力学实验表明,由于涉及溶剂对离子液体进行氘化的快速可逆反应,因此该反应在底物上相对于离子液体为一级伪零级。