摘要:
The reaction of 2,3:4,5-diacetone-D-arabinose with protected dihydroxyacetone catalyzed by L-proline afforded two diastereoisomeric octoses in a 7:1 ratio in 75% yield. The anti (3S,4S) configuration at the newly created stereogenic centers was assigned to the main isomer on the basis of the X-ray analysis. The same reaction when catalyzed with unnatural D-proline provided the same products in a 1:20 ratio. (c) 2012 Elsevier Ltd. All rights reserved.