title: Photoinduced reactions of para-quinones with bicyclopropylidene leading to diverse polycyclic compounds with spirocyclopropanes.
abstract: Photoinduced reactions of bicyclopropylidene (BCP) with para-quinones (p-quinones) including benzoquinones, naphthoquinones, and anthraquinones were found to proceed via different cycloaddition pathways and lead to diverse polycyclic products bearing spiropropyl moiety. Photocycloaddition of BCP with benzoquinones gave spirooxetanes as the primary products, which upon irradiation were able to rearrange into the spiro[4.5]deca-6,9-diene-2,8-diones as secondary photoproducts. Chemoselectivity of the photocycloaddition of BCP with naphthoquinones relies largely on the substitution groups linked to the C═C in between the two carbonyl groups to give different types of products. Photoreaction of BCP with 9,10-anthraquinone gave not only the spirooxetane product, but also a novel spiro[indan-1,1'-phthalan]-3'-one product whose formation might be initiated by a transannular attack of the C4 cyclopropyl radical to the para-carbonyl group. Mechanisms involved in the formation of diverse primary or secondary products in the photoreactions of BCP with p-quinones were proposed. Some of the photoreactions also hold potentials as useful synthetic protocols for important spiropolycyclic compounds such as sesquiterpenes.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Wen-Jie
authors.initials: WJ
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Ching Kheng
authors.initials: CK
authors.lastname: Quah
authors.forename: Hoong-Kun
authors.initials: HK
authors.lastname: Fun
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Xu
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000880:Anthraquinones / Q000737:chemistry*; D016227:Benzoquinones / Q000737:chemistry*; D061565:Cycloaddition Reaction; D003521:Cyclopropanes / Q000737:chemistry; D008027:Light; D015394:Molecular Structure; D009285:Naphthoquinones / Q000737:chemistry*; D055668:Photochemical Processes; D011083:Polycyclic Compounds / Q000138:chemical synthesis*; D013141:Spiro Compounds / Q000737:chemistry
chemical_list: D000880:Anthraquinones; D016227:Benzoquinones; D003521:Cyclopropanes; D009285:Naphthoquinones; D011083:Polycyclic Compounds; D013141:Spiro Compounds