Copper-catalyzed enantioselective conjugate addition of diethylzinc to α,β-unsaturated carbonyl compounds using diphosphonites as chiral ligands

Highly Enantioselective Cu‐Catalyzed Conjugate Additions of Dialkylzinc Reagents to Unsaturated Furanones and Pyranones: Preparation of Air‐Stable and Catalytically Active Cu–Peptide Complexes

“…In spite of high enantioselectivities (>90 % ee ) in select instances, the above disclosures address only reactions of one or two substrates ( I , n =1 or 2) or nucleophiles (typically [Et 2 Zn]; less frequently [Me 2 Zn]). Due to complications that will be clarified later, in a number of cases, isolated yields are not indicated (only % conversion disclosed) 6a,b,d. In addition, two reports provide examples of Cu‐catalyzed ACA of Grignard reagents to lactones ( I , n =2);9a–b in one disclosure,9a high catalyst loading is required (32 mol %; 5–92 % ee ) and the other9b offers only a single example (82 % ee ).…”

Copper‐Catalyzed Enantioselective Conjugate Addition of Grignard Reagents to α,β‐Unsaturated Esters

“…[1] Whereas extraordinary advances have been made in asymmetric 1,4-additions to enones, lactones, and nitroalkenes, [1][2][3][4][5] in the case of acyclic a,bunsaturated esters the progress has been limited, [6] despite the enormous synthetic potential of the resulting enantiopure bsubstituted esters as building blocks for natural product synthesis. [1] Whereas extraordinary advances have been made in asymmetric 1,4-additions to enones, lactones, and nitroalkenes, [1][2][3][4][5] in the case of acyclic a,bunsaturated esters the progress has been limited, [6] despite the enormous synthetic potential of the resulting enantiopure bsubstituted esters as building blocks for natural product synthesis.…”

Formation of All-Carbon Quaternary Centers by Copper-Catalyzed Asymmetric Conjugate Addition

“…whereas with Rh, only aryl and alkenyl groups were transferred, via their boronic acids. Over the years, the Cu-catalyzed asymmetric conjugate addition (ACA) was successfully applied to many different Michael acceptors, such as cyclic [5− 9] and acyclic enones, [10,11] lactones [12,13] or lactames, [14] nitro-olefins, [15− 18] amides [19] and malonates. [20− 22] However, whatever the Michael acceptor, all attempts on substrates bearing a β -disubstituted double bond lacked reactivity, probably for steric reasons (Scheme 1).…”