ENANTIOSELECTIVE SYNTHESIS OF NATURAL DIBENZYLBUTYROLACTONE LIGNANS (-)-ENTEROLACTONE, (-)-HINOKININ, (-)-PLUVIATOLIDE, (-)-ENTERODIOL, AND FUROFURAN LIGNAN (-)-EUDESMIN VIA TANDEM CONJUGATE ADDITION TO GAMMA-ALKOXYBUTENOLIDES

A VANOEVEREN, JFGA JANSEN, BL FERINGA

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

A general and efficient method is described for the asymmetric synthesis of a variety of lignans. 5-(Menthyloxy)-2(5H)-furanones 5 proved to be excellent chiral synthons in this respect and could be transformed with complete stereoselectivity into a number of lignans. The addition of lithiated dithianes 7 to enantiomerically pure butenolides 5 was followed by quenching of the resulting lactone enolate anions with a benzylbromide (9) or with an aldehyde (6). This tandem addition quenching procedure gave the diastereomerically pure adducts 11, 26, or 27 in 50-67% yield, with a carbon skeleton as found in most natural lignans. As examples of the wide applicability of this method, the syntheses of the enantiomerically pure natural lignans (-)-hinokinin (23b), (-)-enterolactone (24a), (-)-pluviatolide (24c), and (-)-enterodiol (25) in overall yields of 29-37% from 5a and (-)-eudesmin (30) in 16% overall yield from 5b are described.

Original languageEnglish
Pages (from-to)5999-6007
Number of pages9
JournalJournal of Organic Chemistry
Volume59
Issue number20
Publication statusPublished - 7-Oct-1994

Keywords

  • OPTICALLY-ACTIVE LIGNANS
  • DIELS-ALDER REACTIONS
  • ASYMMETRIC-SYNTHESIS
  • ENANTIOSPECIFIC SYNTHESIS
  • FEMALE URINE
  • COMPOUND-X
  • 1,4-ADDITIONS
  • MENTHYLOXYBUTENOLIDES
  • PODOPHYLLOTOXIN
  • ENTEROLACTONE

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