Kyo Okada

Synthetic studies on β-lactam antibiotics. Part 16. synthesis of 1-carba-2-penem-3-carboxylic acid esters from penicillins utilizing a carbon-carbon coupling reaction

Abstract Allylazetidinones 9 , 10 , prepared by coupling of allylcoppers 8 with chloroazetidinones 6 , 7 , were converted into carbapenem esters 16 , 28 – 31 using an Emmons-Horner reaction to introduce the 6-side chain and an intramolecular Wittig reaction to form the carbapenem ring system.

Synthetic studies on β-lactam antibiotics. part 11. Completely stereocontrolled synthesis of 7α-unsubstituted 1-oxacephems from penicillins

Abstract A cis intermediate 3 was obtained by novel reductive cleavage of 2 , prepared from 1 in 6 steps including a new ester to ketone conversion. Regioselective bromination of 3 followed by substitution and known conversions gave 1-oxacephems 5 .