Dienol Rearrangements Catalyzed by Nickel Chloride

Keith S. Kyler, A. Bashir Hashemi, David S. Watt

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


The rearrangement of dienols R2C(OH)CH=CHC(X)=CR2 which possess a nonterminal, arylthio or alkylthio substituent was effected by using nickel chloride in aqueous tert-butyl alcohol at 60 °C to furnish the vicinally substituted dienol R2C=CHCH=C(X)CR2(OH). Application of this rearrangement to 24-(methylthio)cholesta-5, 22, 24-trien-20-ol provided 24-(methylthio)cholesta-5, 20(22), 23-trien-25-ol and formed the basis for a new, five-step synthesis of (20fi)-25-hydroxycholesterol from pregnenolone tetrahydropyranyl ether. The rearrangement process appeared to be driven by the relief of unfavorable steric interactions between the quaternary C-13 and C-20 centers in steroids and influenced by the nature of the nickel(II) catalyst. The sulfur-containing substituent was not a prerequisite for the rearrangement since the desulfurized dienols underwent an analogous rearrangement. Preparation of these desulfurized dienols involved the use of a Raney nickel catalyst deactivated by heating in decalin. This catalyst selectively desulfurized vinyl thioethers to olefins.

Original languageEnglish
Pages (from-to)1084-1090
Number of pages7
JournalJournal of Organic Chemistry
Issue number6
StatePublished - Mar 1984

ASJC Scopus subject areas

  • Organic Chemistry


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