Catalytic cycloalumination in steroid chemistry II: selective functionalization of 2'-methylidene-2',3'-ethano-(5α)-cholestane

Steroids. 2013 Dec 11;78(12-13):1298-303. doi: 10.1016/j.steroids.2013.09.007. Epub 2013 Sep 27.

Abstract

The catalytic cycloalumination of 2'-methylidene-2',3'-ethano-(5α)-cholestane with Et3Al catalyzed by Cp2ZrCl2 was performed for the first time to give spiro[2',3'-ethano-(5α)-cholestane-2',3″-aluminacyclopentane] in a ~75% yield and with high stereoselectivity (>98%). The obtained cyclic organoaluminum compound was transformed in situ into heterocyclic spiran derivatives of 2',3'-ethano-(5α)-cholestane.

Keywords: (5α)-Cholestane; Aluminacyclopentane; Cycloalumination; Dzhemilev reaction; Spiranes; Zirconocene dichloride.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Catalysis
  • Cholestanes / chemistry*
  • Coordination Complexes / chemical synthesis*
  • Cycloaddition Reaction
  • Organometallic Compounds / chemistry*
  • Spiro Compounds / chemical synthesis*
  • Zirconium / chemistry*

Substances

  • Cholestanes
  • Coordination Complexes
  • Organometallic Compounds
  • Spiro Compounds
  • Zirconocene dichloride
  • Zirconium
  • triethylaluminum