Synthesis of a 1-oxacephem structurally related to clavulanic acid from D-glucuronolactone

Article abstract of DOI:10.1016/S0040-4020(97)00248-2

[2+2]Cycloaddition of chlorosulfonyl isocyanate to 3-O-vinyl ethers derived from D-glucose and D-glucuronolactone proceeded with an excellent stereoselectivity to provide azetidin-2 ones with (R) configuration at C-4'. Intramolecular N-alkylation afforded 1-oxabicyclic β-lactams having six- or seven-membered ring fused to the four-membered one.