Catalytic enantioselective reaction. Part 9. 1,2-O-Isopropylidene-5-deoxy-5-N,N-dialkyl (or -N-monoalkyl)amino-α-D-xylofuranose derivatives as highly effective chiral catalysts for enantioselective addition of diethylzinc to aliphatic and aromatic aldehydes

Abstract

A series of new 1,2-O-isopropylidene-5-deoxy-5-N,N-dialkyl (or-N-monoalkyl)amino-α-D-xylofuranose derivatives have been prepared form D-xylose and their enantioselectivities as chiral catalysts for the addition of diethylzinc to aldehydes have been examined. Or the chiral catalysts examined, 5-deoxy-1,2-O-isopropylidene-5-morpholino-α-D-xylofuranose provides high enantioselectivity for aromatic and relatively hindered aliphatic aldehydes, and 5-deoxy-5-hexaydroazepinyl-1,2-O-isopropylidene-α-D-xylofuranose is highly effective for unhindered aliphatic aldehydes.