Substitution Reactions Using Organocopper Reagents

Abstract

Carbon‐carbon sigma‐bond formation one of the most fundamental operations in organic chemistry, is often accomplished by interaction of an organometallic reagent with an organic substrate having a suitable leaving group. Selective substitution of halogens and of alcohol derivatives by various hydrocarbon groups in many different types of organic substrates has been achieved most successfully using organocopper reagents. The wide scope and effectiveness of these reagents in coupling with halides and alcohol derivatives have made formation of the unsymmetrical coupling product R‐R' a useful reaction in organic synthesis, allowing efficient and specific substitution of X by alkyl, alkenyl, alkynyl, or aryl groups. Because selective coupling between organic substrate and organocopper reagent is usually achieved more effectively by stoichiometric than by catalytic organocopper reagents, and more effectively still by organocuprates(I) than by mono‐copper or by complexed organocopper reagents, the emphasis in this chapter is on organocuprates (I). Consideration is given to possible mechanisms of substitution reactions using organocopper reagents, to scope, limitations, and synthetic utility of these reactions, and to optimal experimental considerations for their application.

Alkenylcopper Reagents Prepared from Stereodefined Alkenylboronate Esters. Reaction with Allylic Halides as a Convenient Route to Stereodefined 1,4-Dienes

“…The first involved attempted activation or enhancement of copper reagent reactivity. The use of HMPA as a co-solvent has been reported to promote organometallic coupling reactions, including reaction of alkenylcopper reagents with organic halides [17,18]. Thus reaction of allyl chloride with the copper reagent derived from B-1-hexenyl9-BBN in the presence of three equivalents of three equivalents of HMPA afforded a 56% yield of diene 1.…”

Stereoselective Ring Opening of Bicyclic Nitroso Diels-Alder Cycloadducts with Carbon Nucleophiles

“…In the preliminary reaction with Grignard reagents, low yields and selectivities were observed, but two important points were noted: i) only two major products derived from cleavage of the C-O bond were isolated (path B' and C' not observed); (ii) no products arising from attack at the carbonyl group were detected (path A). With the aim to improve yields and selectivities, the reaction was repeated in the presence of copper salts, as this strategy is often used to affect the reactivity of organomagnesium reagents [46]. The combined use of CuCl 2 and vinylmagnesium bromide had a dramatic effect on the yield and selectivity of the reaction providing a 89% yield for of a 7:3:1 ratio of anti-1,2-:anti-1,4-:syn-1,4-hydroxamic acids, and the major anti-1,2-product trans-3a could be isolated cleanly by silica gel chromatography [47] (Scheme 6).…”

Structural Analysis and Reactivity of Tetramethylcopper(III) Complex towards Nitrogen Donor Ligands by Density Functional Theory

“…Copper complexes in the oxidation states +1, +2, and +3 are more common than complexes of Cu(0) and Cu(IV). The Cu(III)-alkyl complexes are used for the effective C-C bond formation at low temperatures [1][2][3][4][5] and several Cu(III)-alkyl intermediates have also been characterized by Rapid Injection NMR technique [6][7][8][9][10][11]. Theoretical studies have been carried out to understand the stability and reactivity of Cu(III)-alkyl complexes [12][13][14][15][16].…”