pre-equilibrium in the formation of iminodiazonium (ID) ion and that the N2 liberation from the ID ion is rate-determining. Under high azide concentration conditions, where the effective reactant is the ID ion, the reaction gave a linear Hammett plot with a ρ value of −0.50. The observed substituent effects on the rate and the product selectivity imply that path bifurcation on the way from the rate-determining
Atom-Economical and Tandem Conversion of Nitriles to <i>N</i>-Methylated Amides Using Methanol and Water
作者:Bhaskar Paul、Milan Maji、Sabuj Kundu
DOI:10.1021/acscatal.9b03916
日期:2019.11.1
A cobalt complex catalyzed tandem conversion of nitrile to N-methylated amide is described using a methanol and water mixture. Using this protocol, several nitriles were directly and efficiently converted to the desired N-methylated amides. Kinetic experiments using H2O18 and CD3OD suggested that water and methanol were the source of the oxygen atom and methyl group, respectively, in the final N-methylated
描述了使用甲醇和水的混合物的钴络合物催化的腈串联转化为N-甲基化酰胺。使用该方案,将几个腈直接有效地转化为所需的N-甲基化酰胺。使用H 2 O 18和CD 3 OD进行的动力学实验表明,水和甲醇分别是最终N中氧原子和甲基的来源。-甲基化酰胺。重要的是,控制实验实现了活性Co(I)–H物种参与该转化的过程。动力学同位素效应(KIE)研究表明,甲醇C–H键的活化是动力学上重要的一步。哈米特图证实了电子不足的腈的反应更快。此外,计算研究支持了从腈形成N-甲基化酰胺的可能途径。
Ruthenium-Catalyzed Synthesis of N-Methylated Amides using Methanol
作者:Bhaskar Paul、Dibyajyoti Panja、Sabuj Kundu
DOI:10.1021/acs.orglett.9b01925
日期:2019.8.2
An efficient synthesis of N-methylated amides using methanol in the presence of a ruthenium(II) catalyst is realized. Notably, applying this process, tandem C-methylation and N-methylation were achieved to synthesize α-methyl N-methylated amides. In addition, several kinetic studies and control experiments with the plausible intermediates were performed to understand this novel protocol. Furthermore
A cobalt‐catalyzed 1,4‐aryl migration/disulfonylation cascade applied to α‐bromo N‐sulfonyl amides was developed. The reaction was highly chemoselective, allowing the preparation of α‐arylamides possessing a variety of functional groups. The method was used as the key step to synthesize an alkaloid, (±)‐deoxyeseroline. Mechanistic investigations suggest a radical process.