Nonenzymatic enantioselective monoacetylation of prochiral 2-protectedamino-2-alkyl-1,3-propanediols utilizing a chiral sulfonamide-Zn complex catalyst.

ABSTRACT

[structure see text] Treatment of a chiral sulfonamide with Et(2)Zn gave quantitatively its Zn complex and then the structure was determined by X-ray crystallographic analysis. Reaction of prochiral N-Boc-2-amino-2-alkyl-1,3-propanediols with Ac(2)O in the presence of 5 mol % of chiral sulfonamide-Zn complex catalyst afforded the corresponding chiral monoacetyl products in 70-92% yields with 70-88% ee values. The proposed mechanism for the catalytic monoacetylation of a prochiral 1,3-propanediol was presented on the basis of CSI-MS analysis.