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
Denitrogenative Hydrotrifluoromethylation of Benzaldehyde Hydrazones: Synthesis of (2,2,2‐Trifluoroethyl)arenes
作者:Zhensheng Zhao、Kevin C. Y. Ma、Claude Y. Legault、Graham K. Murphy
DOI:10.1002/chem.201902818
日期:——
hydrazones of arylaldehydes with Togni's CF3 -benziodoxolone reagent, in the presence of potassium hydroxide and cesium fluoride, induces a denitrogenative hydrotrifluoromethylation event to produce (2,2,2-trifluoroethyl)arenes. This novel reaction was tolerant to many electronically-diverse functional groups and substitution patterns, as well as naphthyl- and heteroaryl-derived substrates. Advantages of this
Copper-Catalyzed Conjugate Addition of Carbonyls as Carbanion Equivalent via Hydrazones
作者:Siyi Luo、Marie Peng、Pierre Querard、Chen-Chen Li、Chao-Jun Li
DOI:10.1021/acs.joc.1c01380
日期:2021.9.17
catalyzed by readily available copper complexes at room temperature. The employment of mesitylcopper(I) and electron-rich phosphine bidentateligand is a key factor affecting reactivity. The reaction allows various aromatic hydrazones to react with diverse conjugated compounds to produce 1,4-adducts in yields of about 20 to 99%.
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。
Umpolung of Carbonyl Groups as Alkyl Organometallic Reagent Surrogates for Palladium-Catalyzed Allylic Alkylation
作者:Dianhu Zhu、Leiyang Lv、Chen-Chen Li、Sosthene Ung、Jian Gao、Chao-Jun Li
DOI:10.1002/anie.201809112
日期:2018.12.10
carbon nucleophiles is difficult and remains a major challenge. Reported here is a highly chemo‐ and regioselective direct palladium‐catalyzed C‐allylation of hydrazones, generated from carbonyls, as a source of umpolung unstabilized alkyl carbanions and surrogates of alkyl organometallicreagents. Contrary to classical allylation techniques, this umpolung reaction utilizes hydrazones prepared not