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Cu 0 ‐Promoted Cyclisation of Unsaturated α‐Halogeno Amides To Give β‐ and γ‐Lactams
Author(s) -
Clark Andrew J.,
Duckmanton Jonathan N.,
Felluga Fulvia,
Gennaro Armando,
Ghelfi Franco,
Hardiman Jack R. D.,
Isse Abdirisak A.,
Manferdini Claudia,
Spinelli Domenico
Publication year - 2016
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201600249
Subject(s) - chemistry , copper , selectivity , medicinal chemistry , solvent , ligand (biochemistry) , stereochemistry , organic chemistry , catalysis , biochemistry , receptor
Efficient 5‐ exo ‐ trig atom‐transfer radical cyclisation of 13 unsaturated α‐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 Na 2 CO 3 (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 β‐lactams, although these reactions gave lower yields (35–76 %).