Highly Diastereoselective Synthesis of Pederic Acid Derivatives.
A highly diastereoselective synthesis of methyl pederate (2) is described. A critical feature of the successful route is the introduction of the key C(7)-stereocenter at the stage of 4 via an enantioselective, syn-selective aldol reaction of aldehyde 5 and the chiral acyl oxazolidinone 6. Aldehyde 5, in turn, was prepared from the readily available aldol derivative 7 via a chelate-controlled reaction with allyltrimethylsilane. Intermediate 4 was elaborated to 2 via the intermediacy of 7-O-(3,4-dimethoxybenzyl)pederic acid (3), an intermediate in Kishi's syntheses of mycalamides A and B and onnamide A, by way of methyl pyranoside 10 and the fully protected pederic acid derivative 11.
Roush
William R.
WR
Department of Chemistry, Indiana University, Bloomington, Indiana 47405.
Marron
Thomas G.
TG
Pfeifer
Lance A.
LA