Syntheses of (+/-)- and Enantiomerically Pure (+)-Longifolene and of (+/-)- and Enantiomerically Pure (+)-Sativene by an Intramolecular de Mayo Reaction

Article abstract of DOI:10.1002/hlca.19840670429

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 (intramolecular de Mayo reaction) in organic synthesis.