Preparation of 3-Benzoylpenems and Penem Amides by Wittig Methodology

Article abstract of DOI:10.1016/0040-4039(95)00767-7

Condensation of phenyl glyoxal with azetidin-2-ones (1a-c) gave the hemi-aminals (2a-c).Subsequent conversions produced the 4-(formylthio)phosphoranes (4a-c) which gave on heating the 3-benzoylpenems (5a-c), formed by intramolecular Wittig cyclisation.Thermal isomerisation of trans-6-substituted-3-benzoylpenems allowed the preparation of the cis-6-substituted-3-benzoylpenems (7a-c).Using similar methodology the penem amides (7d-e) were synthesised.