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A new insoluble polymer containing a Cinchona alkaloid derivative has been synthesized and used as chiral ligand in the heterogeneous enantioselective dihydroxylation of olefins. It is shown that the enantioselectivity of the optically active diols obtained from both aliphatic and aromatic substrates is always comparable to that observed in the homogeneous phase under the same reaction conditions. A method for evaluating the enantiomeric excesses of the optically active products is also described.o 1995 Wiey-Liss, Inc.KEY WORDS: asymmetric dhydroxylation, enantiomeric excesses, polymerization, chiral separation, optically active diolsThe catalytic asymmetric dihydroxylation of oleiins' has evolved during the last decade into one of the most powerful asymmetric reactions in organic chemistry. Indeed, this reaction permits one to obtain two stereospecifically embedded vicinal hydroxyl groups in compounds of well-defined chirality: these chiral diols very frequently show biological activity and they can be widely employed in asymmetric syntheses.Sharpless and co-workers have steady improved the asymmetric dihydroxylation in homogeneous phase by developing several Cinchona alkaloid derivatives' which provide chiral diols from a wide number of olefinic substrates with enantioselectivities which exceed 90% in many cases.To further improve the convenience and economy of the process, a highly attractive approach is presented by the heterogeneous catalytic dihydroxylation employing insoluble polymer bound chiral Cinchona derivatives. S i w c a n t advantages have been pointed out when performing asymmetric dihydroxylation with polymeric supports, particularly because the chiral ligand can be recovered by simple filtration and recycled many times. To date, several notes appeared d e a h g with this procedure.We have recently reported5 the synthesis and use of a polymer containing hydroxyethyl methacrylate, ethylene glycol dunethacrylate and 4-chlorobenzoate of quinine 1 (Fig. l), spaced from the main polymeric chain, which provided diols with enantiomeric excesses (e.e) comparable to those obtained with the free alkaloid under similar reaction conditions.Since it was previously shown6 that the modification of the hydroxylic group at the 9-0 position of the alkaloid is of great importance in obtaining higher e.e. in the homogeneous phase, we felt that on changing the 4-chlorobenzoate ester with a ddferent substituent in the polymer, the enantioselectivity could be improved in the heterogeneous phase.In this study we report7 on the synthesis of polymer 2 (Fig. 1) The results achieved in the catalytic asymmetric reaction using the above polymer are compared to those previously obtained; the enantiomeric excesses of the diols obtained were evaluated by an enantioselective chromatographic method. MATERIALS AND METHODSAll chemicals were purchased from commercial sources and used without further purification. Hydroxyethyl methacrylate and ethylene glycol dimethacrylate were distilled prior to use. 'H-NMR and 13C-NMR spe...

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