CATALYTIC ENANTIOSELECTIVE REACTIONS .9. 1,2-O-ISOPROPYLIDENE-5-DEOXY-5-N,N-DIALKYL (OR E-5-DEOXY-5-N-MONOALKYL)AMINO-ALPHA-D-XYLOFURANOSE DERIVATIVES AS HIGHLY-EFFECTIVE CHIRAL CATALYSTS FOR ENANTIOSELECTIVE ADDITION OF DIETHYLZINC TO ALIPHATIC AND AROMATIC-ALDEHYDES

A series of new 1,2-O-isopropylidene-5-deoxy-5-N,N-dialkyl (or -N-mono alkyl)amino-alpha-D-xylofuranose derivatives have been prepared from a lpha-D-xylose and their enantioselectivities as chiral catalysts for t he addition of diethylzinc to aldehydes have been examined. Of the chi ral catalysts examined, O-isopropylidene-5-morpholino-alpha-D-xylofura nose provides high enantioselectivity for aromatic and relatively hind ered aliphatic aldehydes, and -5-hexahydroazepinyl-1,2-O-isopropyliden e-alpha-D- xylofuranose is highly effective for unhindered aliphatic a ldehydes.