Stereoselective Conversion of Aucubin into Polyfunctionalized Tetrahydro‐1H‐cyclopenta[c]furan Glucosides

Abstract

Mitsunobu reaction of 2′,3′,4′,6′,10‐penta‐O‐pivaloylaucubin (6) with phthalimide, triphenylphosphine, and diethyl azodicarboxylate gave (6R)‐6‐phthalimido‐perpivaloylbartsioside (10) (Scheme 1). Selective oxidation reactions performed with perpivaloylaucubin (12) yielded (1R)‐ and (1S)‐3(β‐D‐glucopyranosyloxy)‐1H‐cyclopenta[c]furan‐1‐carboxaldehydes 13 and 14 respectively (Scheme 2). Similarly, perpivaloyl‐6‐epiaucubin (9) and 10 afforded the corresponding (1S)‐carboxaldehyde 15 and (1R)‐carboxaldehyde 16, respectively. The protected cyclopentafuran glycosides obtained in this way are versatile synthons, which may prove useful for further chemical diversification.

Asymmetric Total Synthesis of the Iridoid β-Glucoside (+)-Geniposide via Phosphine Organocatalysis

“…Glycosidation of lactol 9 employing the trichloroacetimidate as the glycosyl donor delivered the β-glucoside 10 in 62% yield as a single diastereomer. Global deprotection of 10 using aqueous lithium hydroxide in acetonitrile 25 provided (+)-geniposide 1 in 61% isolated yield, the spectral data of which corresponded to that of previously reported material 26…”

Mild and Chemoselective Lactone Ring-Opening with (TMS)ONa. Mechanistic Studies and Application to Sweroside Derivatives

“…We have used them as chiral green bioresources. Indeed, they constitute valuable starting materials for the synthesis of bioactive compounds. ,− Our group has developed new chiral scaffolds and building blocks starting from aucubin ( 1 ), leading to the construction of new heterocyclic systems via their pyran ring contraction or expansion, generating a wide skeletal and chemodiversity. In particular, this has allowed us to prepare new amino acids, enoxysilanes, and aminocyclopentanol glucosidase inhibitors .…”

A novel series of cytotoxic iridoid glucosides derived from aucubin: Design, synthesis and structure–activity relationships

“…Indeed,under Birch conditions [25a], the selective reduction of allylic alcohol of 1 by Li/NH 3 , permitted the obtainment of linaride (10-deoxyaucubin, 8) when the reaction was conducted at À78 C and 6,10-deoxyaucubin (9) when the reaction was conducted at À40 C [25]. In order to prepare 6-O-acetyllinaride (10), peracetyllinaride (11) [25b], quantitatively obtained from 8 by acetylation, was selectively deacetylated using a procedure initially described in the sugar chemistry and previously applied in our group to the selective deacetylation of peracetylaucubin [16,18,26]. Thus, treatment of 11 with a catalytic amount of potassium cyanide, in a 2:1 anhydrous mixture of CH 3 OH and CH 2 Cl 2 , for 3 h at 20 C, gave 10 in 48% yield, accompanied by fully deprotected linaride (8), which could be easily separated from the reaction mixture and recycled.…”