ChemInform Abstract: Enantioselectivity Switch Controlled by N,N′‐Di‐ or N,N,N′,N′‐Tetra‐Substituted Chiral Thiophosphorodiamide Ligands, Structural Relatives of Thioureas, in Catalytic Additions of Diethylzinc to Aldehydes.

Abstract

Abstract We have developed a series of new chiral thiophosphorodiamide ligands derived from (1 R ,2 R )-(+)-1,2-diphenylethylenediamine, which are the structural relatives of thioureas. An investigation into their catalytic properties in asymmetric additions of diethylzinc to aldehydes has shown that N , N , N ′, N ′-tetra-substituted chiral thiophosphorodiamides can give ( R )-secondary alcohols with up to 98% yield and 98% ee, while N , N ′-di-substituted chiral thiophosphorodiamides give ( S )-secondary alcohols with up to 99% yield and 97% ee values. The enantioselectivity switch is highly efficient with a broad substrate scope. We have also proposed hypothetical reaction pathways, which result in an enantioselectivity switch.