100. Syntheses of (±)- and Enantiomerically Pure (+)-Longifolene and of (±)- and Enantiomerically Pure (+)-Sativene by an Intramolecular de Mayo Reaction
     Oppolzer, W.; Godel, T.
     Helv. Chim. Acta 1984, 67, 1154-1167

Starting from 2-cyclopentenoyl chloride ((RS)- or (S)-8), the racemic as well as the enantiomerically pure (+)-sesquiterpenes longifolene ((±)- and (+)-1, resp.) and sativene ((±)- and (+)-2, resp.) were synthesized efficiently by a sequence of nine and ten steps, respectively. The key sequence 10 → 16 → 3 is the first strategic application of an intramolecular photoaddition/retro-aldolization sequence (intramolecularde Mayo reaction) in organic synthesis.

DOI : 10.1002/hlca.19840670429