DIASTEREOSELECTIVE SYNTHESIS OF 6-BROMO-6-(l-HYDROXYETHYL)PENICILLANATEBY CROSS-COUPLING OF 6,6-DIBROMOPENICILLANATE AND ACETALDEHYDE PROMOTED WITH GRIGNARD REAGENTS: ROLE OF AMINE LIGANDS

摘要

Grignard reagent-promoted coupling reaction of diphenylmethyl 6,6-dibromopenicillanate lb with acetaldehyde in the presence of N,N,N',N'',N''-pentamethyldiethylenetriamme took place in a highly diastereoselective manner to give diphenylmethyl (1'R,3S,5R,6S)-6-bromo-6-(l'-hydroxyethyl)penicillanate 2b effectively, which is a potent intermediate for the synthesis of carbapenem antibiotics.