title: Regioselective synthesis of multisubstituted furans via metalloradical cyclization of alkynes with α-diazocarbonyls: construction of functionalized α-oligofurans.
abstract: Co(III)-carbene radicals generated from activation of α-diazocarbonyls by Co(II)-porphyrin complexes have been shown to undergo a new type of tandem radical addition reaction with alkynes that affords five-membered furan structures. The Co(II) complex of 3,5-Di(t)Bu-IbuPhyrin, [Co(P1)], is effective in catalyzing the metalloradical cyclization reaction under neutral and mild conditions. The [Co(P1)]-catalyzed process tolerates a wide range of α-diazocarbonyls and terminal alkynes with varied steric and electronic properties, producing polyfunctionalized furans with complete regioselectivity. The catalytic synthesis features a high degree of functional group tolerance and can be applied iteratively to construct functionalized α-oligofurans.
authors.affiliation: Department of Chemistry, University of South Florida, Tampa, Florida 33620-5250, United States.
authors.forename: Xin
authors.initials: X
authors.lastname: Cui
authors.forename: Xue
authors.initials: X
authors.lastname: Xu
authors.forename: Lukasz
authors.initials: L
authors.lastname: Wojtas
authors.forename: Martin M
authors.initials: MM
authors.lastname: Kim
authors.forename: X Peter
authors.initials: XP
authors.lastname: Zhang
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D003500:Cyclization; D003979:Diazonium Compounds / Q000737:chemistry*; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D008665:Metalloporphyrins / Q000737:chemistry*; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D003979:Diazonium Compounds; D005663:Furans; D008665:Metalloporphyrins; D003035:Cobalt