title: Facile synthesis and palladium-catalyzed cross-coupling reactions of 2,3-bis(pinacolatoboryl)-1,3-butadiene.
abstract: Treatment of 1,1-bis(pinacolatoboryl)ethene with an excess of 1-bromo-1-lithioethene gave 2,3-bis(pinacolatoboryl)-1,3-butadiene in high yield. Palladium-catalyzed cross-coupling of the resulting diborylbutadiene with aryl iodides took place smoothly in the presence of a catalytic amount of Pd(OAc)2/PPh3 and aqueous KOH to give 2,3-diaryl-1,3-butadienes in good yields. The coupling reaction with commercially available 4-acetoxyphenylmethyl chloride under the same conditions followed by hydrolysis of the acetyl groups gave anolignan B in a one-pot manner. A variety of [3]- to [6]dendralenes were synthesized by palladium-catalyzed coupling of the diene or 1,1-bis(pinacolato)borylethene with alkenyl or dienyl halides, respectively, in good yields.
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Katsura Campus, Nishikyo-ku, Kyoto 615-8510, Japan. shimizu@npc05.kuic.kyoto-u.ac.jp
authors.forename: Masaki
authors.initials: M
authors.lastname: Shimizu
authors.forename: Takuya
authors.initials: T
authors.lastname: Kurahashi
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Shimono
authors.forename: Kei
authors.initials: K
authors.lastname: Tanaka
authors.forename: Ikuhiro
authors.initials: I
authors.lastname: Nagao
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Kiyomoto
authors.forename: Tamejiro
authors.initials: T
authors.lastname: Hiyama
mesh_terms: D002070:Butadienes / Q000737:chemistry*; D002384:Catalysis; D010165:Palladium / Q000737:chemistry*