Synthesis of Chiral Sulfamide–Amine Alcohol Ligands for Enantioselective Alkylation of Aldehydes

Abstract

A series of chiral sulfamide–amine alcohols (SAA) (1–6) has been easily synthesized from commercially available chiral amino alcohols. In the absence of Ti(O ⁱ Pr)₄, ligand 4 catalyzed the asymmetric addition of diethylzinc to aromatic aldehydes with moderate to good yields and enantioselectivities.

Keywords:

• Amine alcohols
• asymmetric addition
• diethylzinc
• enantioselectivities

ACKNOWLEDGMENTS

We are grateful to the grants from the National Natural Science Foundation of China (No. 20802046) and the Key Laboratory of Organic Synthesis of Jiangsu Province for financial support.

Notes

^a Et₂Zn/aldehyde/ligand = 2.2:1:0.1; 24 h. In all cases, the isolated yield of the corresponding chiral secondary alcohol was 90–99%.

^b The ee values were determined by GC.

^c The absolute configuration assigned by comparison to literature values.

^a Et₂Zn/aldehyde/ligand = 2.2:1:0.1; 24 h. In all cases, the isolated yield of the corresponding chiral secondary alcohol was 90–99%.

^b The ee values were determined by GC.

^c The absolute configuration assigned by comparison to literature values.

^a Et₂Zn/aldehyde/ligand = 2.2:1:0.1; hexane, rt, 24 h.

^b Isolated yield.

^c The ee values were determined by GC.

^d The absolute configuration assigned by comparison with literature values.

^e The catalytic reaction was performed at 0 °C.