title: N-heterocyclic carbene catalyzed annulation of benzofuran-2,3-diones and enals: a concise synthesis of spiro-bis-lactone.
abstract: The N-heterocyclic carbene catalyzed annulation of benzofuran-2,3-diones and enals via homoenolate intermediates is described. The reaction provided a direct and efficient method for the synthesis of spiro-bis-lactones. The ketone-carbonyl group annulated products and the ester-carbonyl group annulated products can be obtained as major products with good yields by convenient catalyst regulation. Furthermore, commercially available thiazolium salt can also catalyze this reaction with modest yield.
authors.affiliation: Department of Chemistry and State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin, 300071, China.
authors.forename: Ze-Dong
authors.initials: ZD
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Jin-Pei
authors.initials: JP
authors.lastname: Cheng
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D001572:Benzofurans / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D006571:Heterocyclic Compounds / Q000737:chemistry*; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000447:Aldehydes; D001572:Benzofurans; D006571:Heterocyclic Compounds; D007783:Lactones; D013141:Spiro Compounds; C030011:carbene; D008697:Methane