A Convenient Synthesis of 3-Deoxy-D-gluco-2-octulosonate (D-gluco-KDO)

Publisher Website
Google Scholar
Abstract
.beta.-Lithiated acrylates have proven to be versatile pyruvate .beta.-carbanion equivalents which are also useful in D-manno-KDO synthesis. The secondary amine adducts of acetylenedicarboxylate 4-display the same versatility, as demonstrated in this paper. However, on reaction with 2,3:4,5-di-O-isopropylidene-D-arabinose 6, the diastereofacial selectivity is in favor of the gluco-isomer, thus leading with lithiated compounds 4A, preferentially to .alpha.-aminobutenolides 7-(g). The best results were obtained with the morpholine adduct of di-tert.-butyl acetylenedicarboxylate 4d which afforded the gluco-isomer 7d-(g) as an easily separable crystalline material. Its deamination and concomitant deisopropylidenation with trifluoroacetic acid provided the known .alpha.-hydroxy-butenolide 8b-(g), which was transformed via decarboxylation product 9-(g) to D-gluco-KDO 10-(g) thus concluding a convenient four step synthesis of this compound via crystalline intermediates.