Total synthesis of pseudomonic acid C

A versatile approach to the total synthesis of the pseudomonic acids

“…The final carbon-carbon bond forming reaction was the Horner-Emmons coupling of ketone 21 with phosphonate 22 (prepared in 75% yield by the DCC/DMAP mediated coupling methyl 9-hydroxynonanoic acid with diethyl phosphonoacetic acid) giving the E-unsaturated ester 23. Deprotection of the TBS ethers with TBAF gave methyl pseudomonate C 24, with spectroscopic data in accord with those previously reported 7,20 and with [a] D +10.0 (c 0.15, CHCl 3 ). Interestingly our literature search revealed no [a] D value for methyl pseudomonate C derived from natural sources and only that for material prepared by total synthesis.…”

“…Interestingly our literature search revealed no [a] D value for methyl pseudomonate C derived from natural sources and only that for material prepared by total synthesis. 20 Hence a sample of pseudomonic acid C isolated from Ps. fluorescens was methylated giving ester 24 with [a] D +10.7 (c 0.3, CHCl 3 ), in good agreement with the value obtained for our synthetic sample.…”

The Julia Reaction

“…Later, during a total synthesis of (þ)-Pseudomonic acid, Williams et al reported high yields for olefination employing the methyl xanthate derivatives of b-hydroxy sulfones [128]. Another variation has also been successfully applied by Barrish et al [129], while Barton et al developed a modified procedure that circumvented the use of tin hydride [130] (Scheme 3.35).…”

Synthesis of (1, 2‐13C2) 2‐phosphoglycolic acid

“…The solid was triturated with methylene chloride (3mL) and the remaining solvent removed under oil-pump vacuum to afford phosphogl3colic acid (5) (0.040 g, 78%). 'H NMR @20, 300 MHz): 6 (M+Na-2H-).…”