Ionic Iodocarbocyclization Reactions of 4-Alkenyl- and 4-Alkynylmalonate Derivatives

Osamu Kitagawa, Tadashi Inoue, Keiko Hirano, Takeo Taguchi

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

The cyclization reactions of dimethyl 4-alkenylmalonate derivatives 1a–d in the presence of I2 and Ti(Ot-Bu)4 proceed in a highly regio- and stereocontrolled manner (5-exo cyclization and trans addition) to give (iodoalkyl)cyclopentane derivatives 2 or bicyclic lactones 3 through the displacement of the iodide of 2 by an ester group. Iodocarbocyclization reactions of dimethyl [(cycloalkenyl)alkyl]-malonates 1g–i or dimethyl [(methylenecycloalkyl)alkyl]malonates 1j and 1k proceed regio- and stereoselectively to give fused ring compounds or spiro compounds, respectively, as single isomers. Similar reactions of 4-alkynyl derivatives 5 give preferentially E-iodomethylene cyclopentane derivatives 6. An ionic mechanism rather than a radical mechanism is suggested on the basis of the regioselectivity and stereospecificity of the above reactions.

Original languageEnglish
Pages (from-to)3106-3112
Number of pages7
JournalJournal of Organic Chemistry
Volume58
Issue number11
DOIs
Publication statusPublished - 1993 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Organic Chemistry

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