Copper‐Mediated and Copper‐Catalyzed Addition and Substitution Reactions of Extended Multiple Bond Systems

Abstract

Introduction Copper‐Mediated and Copper‐Catalyzed Addition Reactions to Extended Michael Acceptors Copper‐Mediated and Copper‐Catalyzed Substitution Reactions of Extended Substrates Conclusion

Probing Cyanocuprates by Electrospray Ionization Mass Spectrometry

“…Among the different variants of organocuprates, the cyanocuprates are arguably the most popular ones. These reagents easily form by transmetalation of CuCN with organolithium compounds RLi, eq , and find application in conjugate additions, − carbocuprations of alkynes, , epoxide-opening reactions, and nucleophilic substitutions of alkyl halides ,, and sulfonates CuCN → RLi LiCuR false( CN false) → RLi LiCuR 2 · LiCN …”

A New Strategy for the Synthesis of Chiral β-Alkynyl Esters via Sequential Palladium and Copper Catalysis

“…While attractive, this proposal is not without risk, given the complexities associated with regiochemical addition/reduction of extended π-systems. In particular, Cu-mediated conjugate additions to activated enyne substrates result in competitive 1,4- and 1,6-addition pathways, where literature precedent suggests a preference for the latter . To our knowledge, there exists only one example of a copper-catalyzed, asymmetric 1,4-addition of an alkyl aluminum or zinc reagent to an ynenone that was recently reported by Hoveyda and co-workers .…”

Regioselective 1,4-Conjugate Addition of Grignard Reagents to α,β–γ,δ-Dienones and α,β–γ,δ-Dienyl Thiol Esters

“…The first example of regioselective 1,4-addition to a dienone involving Grignard reagents was reported in 1905 and the second in 1951. The use of transition metals (e.g., Cu, , Fe, Pd, Rh, Ir) generally gives high regioselectivity for 1,6-addition to dienyl Michael acceptors. The use of copper reagents shows preference for 1,6-addition, although high 1,4-regioselectivity can sometimes be achieved by change of solvent (e.g., R 3 Al/Cu with nitrodienes) or with very specific substrates such as monocyclic , and bicyclic dienones or monocyclic enynones .…”

“…The use of transition metals (e.g., Cu, , Fe, Pd, Rh, Ir) generally gives high regioselectivity for 1,6-addition to dienyl Michael acceptors. The use of copper reagents shows preference for 1,6-addition, although high 1,4-regioselectivity can sometimes be achieved by change of solvent (e.g., R 3 Al/Cu with nitrodienes) or with very specific substrates such as monocyclic , and bicyclic dienones or monocyclic enynones . For the mono- and bicyclic dienones, regiodivergent 1,6-addition can be achieved with R 2 Zn/Cu­(OTf) 2 and 1,4-addition with RMgX/Cu­(OTf) 2 .…”

“…For the mono- and bicyclic dienones, regiodivergent 1,6-addition can be achieved with R 2 Zn/Cu­(OTf) 2 and 1,4-addition with RMgX/Cu­(OTf) 2 . Although highly regioselective 1,6-additions to α,γ-dienyl carbonyl compounds can be achieved with organocopper reagents, , there appears to be no general protocol not involving specially constructed substrates for achieving regioselective 1,4-additions of organometallic reagents to these systems. In prior work, we found that Grignard reagents in the presence of catalytic quantities of zinc­(II) salts underwent regioselective 1,4-addition to 1-nitrodienes and that the zinc catalysts were necessary for high regioselectivity .…”