Copper complexes of phosphoramidites efficiently catalyzed asymmetricaddition of arylboron reagents to acyclic enones. Importantly, rare 1,4-insertion of arylcopper(I) was identified which led directly to O-bound copper enolates. The new mechanism is fundamentally different from classical oxidative addition/reductive elimination of organocopper(I) on enones.
亚磷酰胺的铜配合物有效地催化芳基硼试剂向无环烯酮的不对称加成。重要的是,鉴定了稀有的芳基铜(I)的 1,4-插入,这直接导致了与 O 结合的铜烯醇化物。新机制与传统的有机铜(I)在烯酮上的氧化加成/还原消除有着根本的不同。
A Cu(<scp>ii</scp>)-based strategy for catalytic enantioselective β-borylation of α,β-unsaturated acceptors
The unique nature and readily availability of Cu(v) species underscores the value of the Cu(v)-based catalyst over an array of well-documented Cu(i)-based catalysts.
Iridium-Catalyzed Aerobic α,β-Dehydrogenation of γ,δ-Unsaturated Amides and Acids: Activation of Both α- and β-C–H bonds through an Allyl–Iridium Intermediate
作者:Zhen Wang、Zhiqi He、Linrui Zhang、Yong Huang
DOI:10.1021/jacs.7b11351
日期:2018.1.17
Direct aerobic α,β-dehydrogenation of γ,δ-unsaturated amides and acids using a simple iridium/copper relay catalysis system is described. We developed a new strategy that overcomes the challenging issue associated with the low α-acidity of amides and acids. Instead of α-C-H metalation, this reaction proceeds by β-C-H activation, which results in enhanced α-acidity. Conjugated dienamides and dienoic acids
Kumulierte Ylide XIX.<sup>1</sup>Acylphosphoniumylide durch kettenverlängernde Difunktionalisierung von Grignard-Verbindungen mit Ketenylidentriphenylphosphoran. Anwendung zur Synthese (<i>E</i>)-α,β-ungesättigter-Ketone und der Königinsubstanz
作者:Hans Jürgen Bestmann、Martin Schmidt、Rainer Schobert
DOI:10.1055/s-1988-27461
日期:——
Cumulated Ylides XIX.1 Chain-lengthening Difunctionalization of Grignard Compounds by Reaction with Ketenylidenetriphenylphosphorane. A New Route to (E)-α,β- Unsatured Ketones and the Queen Substance2 The reaction of Grignard compounds with ketenylidenetriphenylphosphorane and subsequent hydrolysis yields 2-oxoalkylidenetriphenylphosphoranes. The latter undergo Wittig reaction, whereby (E-α,β-unsaturated ketones are obtained. An application of this strategy to the synthesis of carbonyl homologues of Lepidoptera pheromones and the queen substance is shown.