A coordinatively unsaturated ruthenium methoxide as a highly effective catalyst for the halogen atom-transfer radical cyclization of N-allyl dichloroacetamides and related reactions

Yukihiro Motoyama, Shiori Hanada, Kazuya Shimamoto, Hideo Nagashima

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

Atom-transfer radical cyclization (ATRC) catalyzed by coordinatively unsaturated ruthenium alkoxides 4, [(η5-C5Me 5)Ru(OR)]2, is investigated, and ruthenium methoxide 4a (R=Me) is found to exhibit excellent catalytic activity for the cyclization of N-allyl-α,α-dichloroacetamides at ambient temperature. Addition of some amounts of two-electron donor ligands such as pyridine and triphenylphosphine improves the catalyst efficiency to afford the corresponding γ-lactams in high yields. The high catalytic activity of this catalyst system enables to control the diastereoselectivity of this 5-exo cyclization kinetically. The present 4a/pyridine system is also effective for the 4-exo cyclization of N-vinylacetamides to afford the corresponding β-lactams in quantitative yields. The 4a/pyridine system is also active towards the ATRP of methyl methacrylate (MMA) at room temperature to afford the poly(MMA) with narrow molecular weight distributions (Mw/Mn=1.2) at the initial stage.

Original languageEnglish
Pages (from-to)2779-2788
Number of pages10
JournalTetrahedron
Volume62
Issue number12
DOIs
Publication statusPublished - Mar 20 2006

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Halogens
Ruthenium
Cyclization
Lactams
Atoms
Catalysts
Catalyst activity
Temperature
Methacrylates
Atom transfer radical polymerization
Polymethyl Methacrylate
Molecular weight distribution
Molecular Weight
Electrons
Ligands
2,2-dichloroacetamide
pyridine

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

Cite this

A coordinatively unsaturated ruthenium methoxide as a highly effective catalyst for the halogen atom-transfer radical cyclization of N-allyl dichloroacetamides and related reactions. / Motoyama, Yukihiro; Hanada, Shiori; Shimamoto, Kazuya; Nagashima, Hideo.

In: Tetrahedron, Vol. 62, No. 12, 20.03.2006, p. 2779-2788.

Research output: Contribution to journalArticle

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