Efficient 5-exo-trig atom-transfer radical cyclisation of 13 unsaturated alpha-halogeno amides mediated by Cu-0 (copper wire) with tripyridylmethanimine ligand (TPMA; 1 mol-%) in a mixed solvent of EtOAc/EtOH (3: 1) is reported (89-98 %), with recycling of the copper wire. A substantial improvement in conversion and selectivity was obtained when Na2CO3 (5 mol-%) was added to the reaction mixture. The Cu-0 acts as a supplementary activator and reducing agent in a SARA-ATRC process. The protocol was extended to the cyclisation onto alkynes and the formation of beta-lactams, although these reactions gave lower yields (35-76 %).
Titolo: | Cu0-Promoted Cyclisation of Unsaturated α-Halogeno Amides to Give β- And γ-Lactams | |
Autori: | ||
Data di pubblicazione: | 2016 | |
Rivista: | ||
Abstract: | Efficient 5-exo-trig atom-transfer radical cyclisation of 13 unsaturated alpha-halogeno amides mediated by Cu-0 (copper wire) with tripyridylmethanimine ligand (TPMA; 1 mol-%) in a mixed solvent of EtOAc/EtOH (3: 1) is reported (89-98 %), with recycling of the copper wire. A substantial improvement in conversion and selectivity was obtained when Na2CO3 (5 mol-%) was added to the reaction mixture. The Cu-0 acts as a supplementary activator and reducing agent in a SARA-ATRC process. The protocol was extended to the cyclisation onto alkynes and the formation of beta-lactams, although these reactions gave lower yields (35-76 %). | |
Handle: | http://hdl.handle.net/11368/2877014 | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1002/ejoc.201600249 | |
URL: | http://dx.doi.org/10.1002/ejoc.201600249 | |
Appare nelle tipologie: | 1.1 Articolo in Rivista |
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