Chiral thiophosphoramide and selenophosphoramide ligands in the Cu(I)-promoted catalytic enantioselective 1,3-dipolar cycloaddition reactions of azomethine ylides and pyrrole-2,5-dione derivatives

Chiral C2-symmetric diphenylthiophosphoramide ligand L1 prepared from C2-symmetric (1S,2S)-(−)-1,2-diphenylethylenediamine was found to be a fairly effective chiral ligand for Cu(I)-promoted 1,3-dipolar cycloaddition of imines and pyrrole-2,5-dione derivatives to give the corresponding adducts in moderate enantioselectivities and good yields.

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[2-(Diphenoxythiophosphorylamino)-1,2-diphenylethyl]thiophosphoramidic acid O,O′-diphenyl esterC38H34N2O4P2S2Ee = 100%[α]D20=-47.8 (c 0.86, CH2Cl2)Source of chirality: optical resolutionAbsolute configuration: (S,S)

[2-(Diethoxythiophosphorylamino)-1,2-diphenylethyl]thiophosphoramidic acid O,O′-diethyl esterC22H34N2O4P2S2Ee = 100%[α]D20=-18.8 (c 1.16, CH2Cl2).Source of chirality: optical resolution.Absolute configuration: (S,S)

DiethylthiophosphoramidesC22H34N2P2S2Ee = 100%[α]D20=+76.5 (c 0.87, CH2Cl2)Source of chirality: optical resolutionAbsolute configuration: (S,S)