A metal‐free approach for the synthesis of 5‐trifluoromethyl‐1,2,4‐triazoles from trifluoroacetimidoyl chlorides and hydrazones has been achieved under aerobic oxidative conditions. The reaction proceeds through a cascade base‐promoted intermolecular C−N bond formation and iodine‐mediated intramolecular C−N bond oxidative coupling sequence. The protocol features broad substrate scope and can be scaled
hydroalkylation of dienes with stabilized carbon nucleophiles has been made, hydroalkylation of dienes with unstabilized carbon nucleophiles has remained a challenge. In this article, we report a protocol for nickel-catalyzed hydroalkylation of dienes with hydrazones, which serve as equivalents of alkyl carbon nucleophiles. In addition, we developed a protocol for hydroalkenylation of dienes with α,β-unsaturated
Addition reactions of organic carbanion equivalents via hydrazones in water
作者:Yi-Zhan Wang、Qi Liu、Liang Cheng、Song-Chen Yu、Li Liu、Chao-Jun Li
DOI:10.1016/j.tet.2020.131889
日期:2021.1
The addition of organometallic reagents to unsaturated bonds is one of the most powerful tools for carbon–carbon bondformations. Alkylation throughorganometallic reagents requires stoichiometric quantity of metal and tedious anhydrous operation in most cases. Here, we report “umpolung” nucleophilic additions of hydrazones to Michael acceptors, carbonyls and imines in water. Under the catalysis of
acyl-based carbanion equivalents. We herein report an alternative strategy that is based on the use of aldehydes as alkyl carbanion equivalents in a reductive coupling with aryl imines. A wide array of secondary amines can be synthesized in moderate to high yields. This reaction is mediated by hydrazine and catalyzed by ruthenium(II) complexes, and it tolerates various functional groups, such as esters, amides
Ruthenium(<scp>ii</scp>)-catalyzed regioselective 1,6-conjugate addition of umpolung aldehydes as carbanion equivalents
作者:Hyotaik Kang、Chao-Jun Li
DOI:10.1039/d1sc03732c
日期:——
addition of carbon nucleophiles to electron-deficient ketones. Yet, 1,6-conjugate additions of extended conjugated systems largely remain underexplored due to difficulties in controlling the regioselectivity. Herein, we report umpolung aldehydes as carbanion equivalents for highly regioselective 1,6-conjugate addition reactions to unsaturated ketones, with preliminary studies of the enantioselective variant
构建 C-C 键的最有效和最可靠的方法之一涉及将碳亲核试剂共轭加成到缺电子酮上。然而,由于难以控制区域选择性,扩展共轭体系的 1,6-共轭添加在很大程度上仍未得到充分探索。在这里,我们报告了 umpolung 醛作为碳负离子等价物,用于对不饱和酮进行高度区域选择性的 1,6-共轭加成反应,并对对映选择性变体进行了初步研究。钌( II )催化剂和富电子二齿膦配体的协同作用对于温和反应条件下的反应性和选择性至关重要。