Copper 1,4-conjugate additions

Keywords Organozinc, Organolithium, Grignard reagent, Copper, Conjugate addition, Nucleophilic addition, Alkylation, Activated olefin, Enone, Nitroalkene, p-Substituted carbonyl... 

Cho reported the addition of alkyl radicals from alkyl iodide to a,P-unsaturated ketones, esters, and nitriles mediated by indium in aqueous media. Recently, enantiomeiically pure natural and unnatural a-amino acids have been synthesized from a chiral methyleneoxazolidinone by such a highly diastereoselective 1,4-conjugate addition of alkyl iodides in aqueous media (Eq. 10.31). The zinc-copper conjugate addition reaction exhibits high chemoselectivity with the possibility of using functionalized iodides to afford a single diastereomer in short reaction times with good yields. 

Copper Conjugate addition of Grignard reagents to cyclic enones (249), catalysed by the Cu complex of Taniaphos (248), followed by Mannich reaction of the resulting chiral magnesium enolates with Af-protected imines, has been shown to produce the adducts (250) with <98% ee. Diastereoselectivity turned out to be dependent on the... 

House investigated the role of cuprous ions in the conjugate addition of organometallic reagents. He found that the catalytic effect can be explained by the intervention of a methyl copper derivative, which reacts rapidly with the carbon-carbon double bonds of the conjugated system. 

Copper-mediated Diastereoselective Conjugate Addition and Allylic Substitution Reactions... 

Copper-catalyzed Enantioselective Conjugate Addition Reactions of Organozinc Reagents... 

A remarkable number of new BINOL- and TADDOL-based diiral ligands for tlie copper-catalyzed conjugate addition of R Zn reagents have recently been introduced, witli botli monodentate and bidentate ligands having proven capable of inducing bigli enanboselectivities [6, 11, 12, 46]. 

Conjugate addition [2] to Midiael acceptors is die most important and usefid reaction in orgatiocopper diemistiy, and die reaction is ofien used as die key step in die syndiesis of numerous natural and unnatural products. Perhaps one of die most efficient methods for die syndiesis of quaternary carbon centers is organo-copper-mediated conjugate addidon to /, / -disubstituted enones. 

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