A comparative study of remote oxy-functionalization of unactivated carbonsin 5β-steroids by dimethyldioxirane and 2,6-dichloropyridineN-oxide/ruthenium-porphyrin/HBr

Takashi Iida, Shoujiro Ogawa, Keisuke Shiraishi, Genta Kakiyama, Takaaki Goto, Nariyasu Mano, Junichi Goto

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Remote oxy-functionalization of methyl 3α-acetoxy- and 3-oxo-5β-cholan-24-oates with 2,6-dichloropyridine (DCP) N-oxide catalyzed by (5,10,15,20-tetramesitylporphyrinate) ruthenium (II) carbonyl complex [Ru(TMP)CO] and HBr was compared with that with dimethyldioxirane (DMDO). Treatment of the 5β-steroids with DMDO afforded the corresponding 5β- and 17α-monohydroxylated and 5β,14α- and 5β,17α- dihydroxylated compounds. On the other hand, the corresponding 20S-mono- and 5β,20S-dioxygenated derivatives (as the -lactones), along with 5β-hydroxy compounds, were found to be the major oxidation products of the 5β-steroids with the DCP N-oxide/Ru(TMP)CO/HBr system. Both the reagents oxidized unactivated methine carbons stereoselectively, but the degree of regioselectivity depended upon the oxidants employed and the structure of the hydroxyl-protecting groups at C-3 (acetoxyl or carbonyl) of the substrates.

Original languageEnglish
Pages (from-to)171-179
Number of pages9
JournalArkivoc
Volume2003
Issue number8
Publication statusPublished - 2003 Dec 1

Keywords

  • 2,6-dichloropyridine N-oxide/ruthenium porphyrin/HBr
  • 5β-steroids
  • Dimethyldioxirane
  • Hydroxylation
  • Ketonization
  • Remote oxy-functionalization

ASJC Scopus subject areas

  • Organic Chemistry

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