Three routes were investigated for the conversion of D-glucose into the title compound. In the first approach, reduction of the 5,6-thiirane ring of 5,6-dideoxy-5,6-epithio-1,2-O-isopropylidene-α-D-glucofuranose (17) as well as that of its 3-O-allyl derivative (13) with lithium aluminium hydride was investigated: 17 afforded the corresponding 6-deoxy derivative besides di-, tri-, and polymers, whereas only polymers were formed from 13. In the second approach, the oxirane ring of 3-O-allyl-5,6-anhydro-1,2-O-isopropylidene-β-L-idofuranose was reduced by sodium borohydride and the resulting 6-deoxy derivative was converted into the 5-thiobenzoate; the corresponding hex-4-enofuranose was formed as a byproduct. In the third approach partial mesylation of methyl 5-thio-α-D-glucopyranoside was attempted, but the 6-mesylate 27 could be isolated only in modest yield (28%) together with rearranged 2,5-thioanhydromannofuranoside derivatives. The mechanism of this rearrangement is discussed in detail. The 6-mesylate 27 was converted via the 6-iodo derivative into the title compound.
- reaction mechanism
- rearrangement reactions of mesylated methyl 5-thio-α-D-glucopyranoside
- reduction of 5,6-thiirane rings with LiAlH
- transannular participation of the sulfur atom
ASJC Scopus subject areas
- Analytical Chemistry
- Organic Chemistry