Thioether-based copper(I) Schiff base complex as a catalyst for a direct and asymmetric A3-coupling reaction

A novel thiosalen ligand based on a thioether has been prepared and readily coordinated with copper(I) salts (CuCl, CuBr, CuI, and CuCN). The new organometallic catalyst was used for the direct and enantioselective alkynylations of imines in an A3-coupling reaction. In this reaction, the corresponding propargylamines were obtained as single products in excellent yields and with good enantioselectivities.

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(+)-4-(1,3-Diphenylprop-2-yn-1-yl)morpholineC19H19NO44% ee (chiral HPLC)[α]D20=+50.3 (c 1.35, CDCl3)Source of chirality: asymmetric synthesis by chiral catalystAbsolute configuration: not determined

(+)-4-(3-Phenyl-1-(p-tolyl)prop-2-yn-1-yl)morpholineC20H21NO[α]D20=+37.2 (c 1.10, CDCl3); 43% ee (chiral HPLC)Source of chirality: asymmetric synthesis by chiral catalystAbsolute configuration: not determined

(−)-4-(1-(4-Nitrophenyl)-3-phenylprop-2-yn-1-yl)morpholineC19H18N2O3[α]D20=-28.3 (c 0.85, CDCl3); 58% ee (chiral HPLC)Source of chirality: asymmetric synthesis by chiral catalystAbsolute configuration: not determined

(+)-N,N-Dimethyl-4-(1-morpholino-3-phenylprop-2-yn-1-yl)anilineC21H24N2O[α]D20=+30.7 (c 0.85, CDCl3); 54% ee (chiral HPLC)Source of chirality: asymmetric synthesis by chiral catalystAbsolute configuration: not determined

(+)-4-(1-(3-Methoxyphenyl)-3-phenylprop-2-yn-1-yl)morpholineC20H21NO2[α]D20=+58.0 (c 1.5, CDCl3); 57% ee (chiral HPLC)Source of chirality: asymmetric synthesis by chiral catalystAbsolute configuration: not determined

(+)-4-(1-(2-Chlorophenyl)-3-phenylprop-2-yn-1-yl)morpholineC19H18ClNO[α]D20=+54.8 (c 2.0, CDCl3); 69% ee (chiral HPLC)Source of chirality: asymmetric synthesis by chiral catalystAbsolute configuration: not determined

(+)-4-(1-(4-Chlorophenyl)-3-phenylprop-2-yn-1-yl)morpholineC19H18ClNO[α]D20=+74.6 (c 2.0, CDCl3); 43% ee (chiral HPLC)Source of chirality: asymmetric synthesis by chiral catalystAbsolute configuration: not determined

(+)-4-(1-(3-Nitrophenyl)-3-phenylprop-2-yn-1-yl)morpholineC19H18N2O3[α]D20=+41.0 (c 1.6, CDCl3); 62% ee (chiral HPLC)Source of chirality: asymmetric synthesis by chiral catalystAbsolute configuration: not determined

(+)-4-(1-(Furan-2-yl)-3-phenylprop-2-yn-1-yl)morpholineC17H17NO2[α]D20=+22.7 (c 0.7, CDCl3); 51% ee (chiral HPLC)Source of chirality: asymmetric synthesis by chiral catalystAbsolute configuration: not determined