Enantioselective copper(II)-catalyzed conjugate addition of diethylzinc to β-substituted enones utilizing BINOL-based phosphoramidite ligands

A family of new chiral phosphoramidite ligands based on 3,3′-disubstituted (S)-BINOL have been successfully synthesized. The chiral phosphoramidite ligands were subsequently applied to the copper(II)-catalyzed enantioselective addition of diethylzinc to β-substituted enones, giving the desired chiral adducts with enantioselectivities of up to 93% ee and high yields (up to 88%).

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(S)-2,6-Bis((benzyloxy)methyl)-N,N-dimethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amineC38H34NO4P[α]D20 = +352 (c 0.2, CHCl3)Source of chirality: (S)-BINOLAbsolute configuration: (S)

(S)-2,6-Bis((benzyloxy)methyl)-N,N-diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amineC40H38NO4P[α]D20 = +363 (c 0.2, CHCl3)Source of chirality: (S)-BINOLAbsolute configuration: (S)

(S)-2,6-Bis((benzyloxy)methyl)-N,N-diisopropyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amineC42H42NO4P[α]D20 = +356 (c 0.1, CHCl3)Source of chirality: (S)-BINOLAbsolute configuration: (S)

(S)-2,6-Bis((benzyloxy)methyl)-N,N-diphenyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amineC48H38NO4P[α]D20 = +107 (c 0.1, CHCl3)Source of chirality: (S)-BINOLAbsolute configuration: (S)

(S)-2,6-Bis((benzyloxy)methyl)-N,N-bis((R)-1-phenylethyl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amineC52H46NO4P[α]D20 = +27.1 (c 0.1, CHCl3)Source of chirality: (S)-BINOLAbsolute configuration: (S) (R)

(S)-2,6-Bis(benzyloxy)-N,N-dimethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amineC36H30NO4P[α]D20 = +415 (c 0.1, CHCl3)Source of chirality: (S)-BINOLAbsolute configuration: (S)

(S)-2,6-Bis(benzyloxy)-N,N-diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amineC38H34NO4P[α]D20 = +366 (c 0.1, CHCl3)Source of chirality: (S)-BINOLAbsolute configuration: (S)

(S)-2,6-Bis(benzyloxy)-N,N-diisopropyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amineC40H38NO4P[α]D20 = +248 (c 0.1, CHCl3)Source of chirality: (S)-BINOLAbsolute configuration: (S)

(S)-2,6-Bis(benzyloxy)-N,N-diphenyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amineC46H34NO4P[α]D20 = +189 (c 0.1, CHCl3)Source of chirality: (S)-BINOLAbsolute configuration: (S)

(S)-2,6-bis(Benzyloxy)-N,N-bis((R)-1-phenylethyl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amineC50H42NO4P[α]D20 = +78 (c 0.1, CHCl3)Source of chirality: (S)-BINOLAbsolute configuration: (S) (R)