accomplished the synthesis of 2-substituted benzofuran derivatives by the palladium-catalyzed reaction of 3-substituted propargylic carbonates with phenols. The 2-substituted benzofuran derivatives were obtained through the intermolecularcoupling of the 3-substituted propargylic carbonates with phenols, and sequential intramolecular cyclization reaction.
catalytic reduction of propargyl carbonates to allenes mediated by a nickel molecular catalyst. The catalytic system uses light as the driving force and amine as the sole hydrogen source. Contrary to other catalytic approaches, the process proceeds without the intermediacy of metal hydride species. The commonly observed pathway in transitionmetalcatalyzed reductive processes is replaced by a pathway
在此,我们报道了由镍分子催化剂介导的碳酸炔丙酯催化还原为丙二烯。该催化系统使用光作为驱动力,胺作为唯一的氢源。与其他催化方法相反,该过程的进行无需金属氢化物物质的中介。过渡金属催化还原过程中常见的途径被涉及一系列电子转移和质子转移的途径所取代。使用这种催化方法,可以在温和条件下获得多种丙二烯。实验研究支持三烷基胺作为还原剂和质子源的双重作用,并揭示了该反应的关键机理特征。提出了Ni( II ) 联烯基中间体的关键原脱镍步骤来解释还原过程。最后,我们还证明选择性 S N 2 ' 还原过程也可以通过电化学方法有效驱动。
Highly selective synthesis of tetra-substituted furans and cyclopropenes: copper(i)-catalyzed formal cycloadditions of internal aryl alkynes and diazoacetates
作者:Andrew K. Swenson、Kate E. Higgins、Matthew G. Brewer、William W. Brennessel、Michael G. Coleman
DOI:10.1039/c2ob26295a
日期:——
A convenient Cu(I)-catalyzed cycloaddition of electron rich internal aryl alkynes and diazoacetates was discovered for the chemoselective and regioselective synthesis of tetra-substituted furans and cyclopropenes in moderate isolated yields (18–67%), and alkyne conversion (29–73%).