Stereoselective Synthesis of Coreoside D and Determination of Its Absolute Configuration

Abstract

We report the stereoselective synthesis of (3S)- and (3R)-coreoside D. The conjugated diyne in the C1–C14 moiety was synthesized through two types of palladium-catalyzed cross-coupling reaction. The introduction of the glucopyranose was achieved by a glycosylation reaction using an imidate derivative in the presence of a Lewis acid. The asymmetric center at the C3-position was constructed by the chiral-pool method using d-malic acid. The stereochemistry at the C3-position of the natural product was determined to be R by comparing the [α]D values of the synthetic stereoisomers with that reported for the natural product.

Polyacetylene Glycosides: Isolation, Biological Activities and Synthesis

“…Concomitant removal of protective groups with Ogawa recently described the stereoselective syntheses of (3S)-coreoside D, 31 and its (3R)-isomer after 18 steps with an overall yield of 7.6 %. [181] The key intermediate 111, which contains the aglycone stereocenter at C3 was synthesized using Horner-Wadsworth-Emmons and Takai reactions from Dmalic acid. Further Sonogashira coupling reaction with diyne 112 gave the advanced intermediate 113 which was submitted to a glycosylation reaction with imidate 114 to give the corresponding acetal.…”