title: AuCl(3)-catalyzed benzannulation: synthesis of naphthyl ketone derivatives from o-alkynylbenzaldehydes with alkynes.
abstract: The reaction of o-alkynylbenzaldehydes 1 and alkynes 2 in the presence of a catalytic amount of AuCl3 in (CH2Cl)2 at 80 degrees C gave naphthyl ketone products in high yields. The AuCl3-catalyzed formal [4 + 2] benzannulation proceeds most probably through the coordination of the triple bond of 1 to AuCl3, the formation of benzo[c]pyrylium auric ate complex via the nucleophilic addition of the carbonyl oxygen atom, the Diels-Alder addition of alkynes 2 to the auric ate complex, and subsequent bond rearrangement. Similarly, the AuCl3-catalyzed reactions of o-alkynylacetophenone and o-alkynylbenzophenone with phenylacetylene afforded the corresponding naphthyl ketone products in good yields.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Asao
authors.forename: Kumiko
authors.initials: K
authors.lastname: Takahashi
authors.forename: Sunyoung
authors.initials: S
authors.lastname: Lee
authors.forename: Taisuke
authors.initials: T
authors.lastname: Kasahara
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Yamamoto