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 language | English |
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Pages (from-to) | 408-416 |
Number of pages | 9 |
Journal | Tetrahedron |
Volume | 67 |
Issue number | 2 |
DOIs | |
Publication status | Published - 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