A green way to γ-lactams through a copper catalyzed ARGET-ATRC in ethanol and in the presence of ascorbic acid

Roberto Casolari, Fulvia Felluga, Vincenzo Frenna, Franco Ghelfi, Ugo M. Pagnoni, Andrew F. Parsons, Domenico Spinelli

Research output: Contribution to journalArticlepeer-review

Abstract

A 'green' ARGET-ATRC, for the CuCl[PMDETA] catalysed cyclo-isomerization of N-allyl-alpha-polychloroamides to gamma-lactams is described. The process works efficiently (yields 78-96%), uses a bio-solvent, as ethanol, and exploits the reducing feature of ascorbic acid to limit, at a low level (2-4%), the amount of catalyst. To preserve the efficacy of the catalytic cycle, addition of Na2CO3 is essential, which quenches the HCl released during the CuCl[PMDETA] regeneration step. Profitable features of the process are: mild reaction temperatures (25-37 degrees C), relatively short reaction times (usually 5 h) and low solvent volumes (2 mmol of substrate/mL of ethanol). The method, upon stoichiometric adjustment, was also used for the synthesis of alpha,beta-unsaturated-gamma-lactams from N-(2-chloroallyl)-alpha-polychloroamides, via a tandem process involving an ATRC and a reductive [1,2]-elimination. (C) 2010 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)408-416
Number of pages9
JournalTetrahedron
Volume67
Issue number2
DOIs
Publication statusPublished - 14 Jan 2011

Keywords

  • Halocompounds
  • ATRC
  • gamma-Lactams
  • CuCl
  • Ascorbic acid
  • TRANSFER RADICAL POLYMERIZATION
  • ADDITION ATRA
  • FUNCTIONAL REARRANGEMENT
  • ORGANIC-SYNTHESIS
  • ELECTRON-TRANSFER
  • REDUCING AGENTS
  • CYCLIZATION REACTIONS
  • METHYL-METHACRYLATE
  • STEREOSELECTIVE-SYNTHESIS
  • DIRUTHENIUM AMIDINATE

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