铱催化异羟肟酸衍生物参与的分子间N-N键偶联反应合成酰肼

Iridium-Catalyzed Intermolecular N-N Coupling for Hydrazide Synthesis Using N-Benzoyloxycarbamates as Acyl Nitrene Precursor

报道了一类铱催化下异羟肟酸衍生物作为酰基氮宾前体参与的分子间N—N偶联合成酰肼化合物的反应.与之前报道的二噁唑酮参与的反应不同,该类氮宾前体不仅可以合成N-酰基肼类化合物,又可以用于N-氧酰基肼类化合物的合成.计算化学研究说明分子内氢键辅助N—O键断裂脱酸形成金属酰基氮宾中间体可能是决速步,随后芳胺在氢键辅助下亲核进攻金属酰基氮宾形成N—N键.

An iridium-catalyzed intermolecular N—N coupling reaction using various N‑benzoyloxyamides as acyl nitrene precursor for hydrazide synthesis has been developed.Unlike the carboxylic acid-derived dioxazolones used in previous report,this type of precursors allows the efficient synthesis of both acyl and oxycarbonyl substituted hydrazines from readily accessible precursors.Computational chemistry studies indicated that formation of the metal-acylnitrenoid intermediates via intramolecular hydrogen bond-assisted N—O cleavage may be the rate-determining step,and the subsequent nucleophilic attack of metal-acylnitrenoid by arylamines may be assisted by Cl…HN hydrogen bond to form the N—N bond.