Enantioselective synthesis of trans-octahydro-1,6-dioxoinden-4-ylpropionic acid from (R)-2,3-O-isopropylideneglyceraldehyde by tandem orthoester Claisen rearrangement

Abstract

The optically active trans-octahydrodioxoinden-4-ylpropionic acid (6) was synthesized via the methylcyclopentanone (8) which was constructed through consecutive orthoester Claisen rearrangement of compounds (9) and (12) derived from (R)-2,3-O-isopropylideneglyceraldehyde (1). Compounds (31) and (32), possessing trans-ring fusion, were prepared by Dieckmann condensation of the corresponding dimethyl esters (27) and (28) which were derived from the regio- and stereo-selective alkylation of the methylcyclopentanone (8), and then orthoester Claisen rearrangement of the allyl alcohol (26).