Synthetic studies directed toward amphidinol 2: elucidation of the relative configuration of the C1–C10 fragment

Abstract

Model compounds ( 11 and 12) for the C1–C10 tetrahydropyran fragment of amphidinol 2 were prepared from (2 S)-benzyloxypropanal in 9 steps. The synthetic route relied on diastereoselective diene-aldehyde cycloaddition, stereoselective C-allylation, and reagent based enantioselective aldehyde allylation. Comparison of the NMR spectra for models 11 and 12 with that for amphidinol 2 indicated that the C1–C10 segment of the natural product possesses the 2 R ∗,4 R ∗,6 R ∗,7 S ∗ ,8 R ∗ ,10 S ∗ relative configuration.