title: Synthesis of phenanthrenes through copper-catalyzed cross-coupling of N-tosylhydrazones with terminal alkynes.
abstract: A novel protocol for the synthesis of phenanthrenes through the copper-catalyzed reaction of aromatic tosylhydrazones with terminal alkynes is explored. The reaction proceeds via the formation of an allene intermediate and subsequent six-π-electron cyclization-isomerization, affording phenanthrene derivatives in good yields. The transformation can be performed in two ways: (1) with N-tosylhydrazones derived from [1,1'-biphenyl]-2-carbaldehydes and terminal alkynes as the starting materials and (2) with N-tosylhydrazones derived from aromatic aldehydes and 2-alkynyl biphenyls as the starting materials. This new phenanthrene synthesis uses readily available starting materials and a cheap copper catalyst and has a wide range of functional group compatibility.
authors.affiliation: Beijing National Laboratory of Molecular Sciences (BNLMS), Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, College of Chemistry, Peking University , Beijing 100871, China.
authors.forename: Mohammad Lokman
authors.initials: ML
authors.lastname: Hossain
authors.forename: Fei
authors.initials: F
authors.lastname: Ye
authors.forename: Zhenxing
authors.initials: Z
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Xia
authors.forename: Yi
authors.initials: Y
authors.lastname: Shi
authors.forename: Lei
authors.initials: L
authors.lastname: Zhou
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jianbo
authors.initials: J
authors.lastname: Wang
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D001713:Biphenyl Compounds / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D006835:Hydrazones / Q000737:chemistry*; D015394:Molecular Structure; D010616:Phenanthrenes / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000447:Aldehydes; D000480:Alkynes; D001713:Biphenyl Compounds; D006835:Hydrazones; D010616:Phenanthrenes; D003300:Copper