Synthetic Approaches to Novel Thiosugar Scaffolds Containing α,β‐Unsaturated Carbonyl Groups

Abstract

The synthesis of new classes of highly functionalized thiosugar derivatives containing α,β‐unsaturated carbonyl functions has been accomplished through simple and efficient strategies. 5‐Thiosugar‐fused butenolides and a 5‐thiohex‐1‐enopyran‐3‐ulose were constructed from easily available starting 3‐uloses by practical and reliable approaches. The reaction sequence used for the bicyclic fused derivatives involved Wittig olefination of protected pento‐ or hexofuran‐3‐uloses, introduction of a sulfhydryl group at C‐5 of the intermediate unsaturated ester and acid‐promoted deprotection, which allowed intramolecular lactonization and conversion into the 5‐thiopyranose form. For the synthesis of a 5‐thiohex‐1‐enopyran‐3‐ulose, a sulfhydryl functionality was introduced at C‐5 on a masked 3‐ulose derived from 1,2:5,6‐di‐O‐isopropylidene‐α‐D‐ribo‐hexofuranos‐3‐ulose. Acidhydrolysis displaced the equilibrium towards the 5‐thiopentopyran‐3‐ulose, which on pyridine‐mediated acetylation underwent 1,2‐elimination of acetic acid to give the desired α,β‐unsaturated 5‐thiopyranulose. This straightforward pathway provided the target compound in 37 % overall yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Synthesis of sulfur karrikin bioisosteres as potential neuroprotectives

“…In order to overcome this problem a new strategy was developed. We combined the synthetic protocol of Goddard-Borger [ 24 ] for the preparation of 2 using the Xavier’s procedure [ 33 ] towards 5-thiopyranose-fused butenolides and the reaction pathway is outlined in Scheme 5 .…”

“…The synthesis of the key intermediate butenolide 23 was accomplished starting from easily available ᴅ-xylose, following a published multistep procedure [ 33 ]. The synthesis of target compound 26 was accomplished in two steps by double esterification and elimination of 23 .…”

3,5-Di-O-benzoyl-1,2-O-isopropylidene-α-D-ribo-hexos-3-ulo-1,4:3,6-difuranose

“…E67, o1800 [doi:10.1107/S1600536811024317] 3,5-Di-O-benzoyl-1,2-O-isopropylidene-α-D-ribo-hexos-3-ulo-1,4:3,6-difuranose Qiurong Zhang, Xuebin Chen, Nan Zhu, Tengfei Jiang and Hongmin Liu S1. Comment C 23 H 22 O 8 , (I), is an important intermediate in the synthesis of bicyclo-glycosyls (Zhang et al, 2011), whose nucleoside derivatives play a vital role as anti-tumour and antivirus agents have been synthesised (Xavier et al 2009;Rajwanshi et al 1999).…”

Exploitation of Furanoid 5‐Azido‐3‐C‐Branched‐Chain Sugars Towards Highly Functionalized Nitrogen‐Containing Carbohydrate Derivatives

“…[8] This biological profile prompted the acquisition of pyranose-fed butenolides [9] and related thiosugar hybrid molecules. [10] These bicyclic compounds were synthesized by a strategy involving the Wittig olefination of appropriately protected pento-or hexofuranos-3-ulose derivatives and subsequent acid hydrolysis of the intermediate furanose-3-C-branched α,β-unsaturated esters (Scheme 1). Within this latter step, cleavage of the protecting groups occurred with concomitant intramolecular lactonization and furanose-topyranose ring expansion.…”