A synthesis of moenocinol from isoprenoid precursors
A synthesis of 5 based on synthons 3,6,7 is suninarized. INTRODUCTION The antibiotic Moenomycin A (1) 1 is the main constituent of the commercial product flavomy— cm R which is employed in animal nutrition.2 1 is an efficient inhibitor of the biosynthesis of the peptidoglycans of bacterial cell—walls by interacting with the enzyme(s) 3 that catalyze the transfer of the disaccharide—oligopeptide unit from the disaccharide—(oligopep— tide)—pyrophosphoryl—undecaprenol intermediate to the growing linear peptidoglycan chain. From degradation 5 and biochemical studies 6, it was concluded that only units E,F,G,H, and I of 1 are essential for full biological (in vitro) activity. Unit I which is linked to the 2—position of D—phosphoglycerate is a unique C25 lipid alcohol called moenocinol,7 On mild acid hydrolysis the allyl ether bond is selectively cleaved and moenocinol (5) is liberated from the rest of the molecule.1,2 Three isoprene units can easily be identified in 5 whereas the central C10 part (C—S through C—22) does not obey the isoprene rule in an obvious way.