title: Intramolecular ipso-halocyclization of 4-(p-unsubstituted-aryl)-1-alkynes leading to spiro[4,5]trienones: scope, application, and mechanistic investigations.
abstract: A new, general method for the synthesis of spiro[4,5]trienones is described by the intramolecular ipso-halocyclization of 4-(p-unsubstituted-aryl)-1-alkynes. In the presence of halide electrophiles, a variety of 4-(p-unsubstituted-aryl)-1-alkynes underwent the intramolecular ipso-halocyclization with water smoothly, affording the corresponding halo-substituted spiro[4,5]trienones in moderate to good yields. The obtained spiro[4,5]trienones can be applied in constructing the azaquaternary tricyclic skeleton via Pd-catalyzed Heck reaction. Notably, the prepared spiro[4,5]trienones and azaquaternary tricycles are of importance in the areas of pharmaceuticals and agrochemicals. The mechanism of the intramolecular ipso-halocyclization reaction is also discussed according to the (18)O-labeling experiments and DFT calculations.
authors.affiliation: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education), Hunan Normal University, Changsha 410081, China.
authors.forename: Bo-Xiao
authors.initials: BX
authors.lastname: Tang
authors.forename: Yue-Hua
authors.initials: YH
authors.lastname: Zhang
authors.forename: Ren-Jie
authors.initials: RJ
authors.lastname: Song
authors.forename: Dong-Jun
authors.initials: DJ
authors.lastname: Tang
authors.forename: Guo-Bo
authors.initials: GB
authors.lastname: Deng
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Wang
authors.forename: Ye-Xiang
authors.initials: YX
authors.lastname: Xie
authors.forename: Yuan-Zhi
authors.initials: YZ
authors.lastname: Xia
authors.forename: Jin-Heng
authors.initials: JH
authors.lastname: Li
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D011789:Quantum Theory; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D000480:Alkynes; D013141:Spiro Compounds; D010165:Palladium