Cu0‐Promoted Cyclisation of Unsaturated α‐Halogeno Amides To Give β‐ and γ‐Lactams. Issue 14 (26th April 2016)

• Record Type: Journal Article
• Authors: Clark, Andrew J.; Duckmanton, Jonathan N.; Felluga, Fulvia; Gennaro, Armando; Ghelfi, Franco; Hardiman, Jack R. D.; Isse, Abdirisak A.; Manferdini, Claudia; Spinelli, Domenico
• Is Part Of: European journal of organic chemistry. Issue 14(2016)
• Page Start: 2479
• Page End: 2491
• Publication Date: 2016-04-26
• Subjects: Radical reactions -- Redox chemistry -- Cyclization -- Copper -- Homogeneous catalysis -- Nitrogen heterocycles; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201600249
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: 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 Na2 CO3 (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 %). Abstract : 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. The protocol was extended to the cyclisation onto alkynes and the formation of β‐lactams (35–76 %).