Regioselective Synthesis of Substituted Naphthalenes: A Novel de Novo Approach Based on a Metal-Free Protocol for Stepwise Cycloaddition of <i>o-</i>Alkynylbenzaldehyde Derivatives with Either Alkynes or Alkenes
作者:José Barluenga、Henar Vázquez-Villa、Alfredo Ballesteros、José M. González
DOI:10.1021/ol035691t
日期:2003.10.1
o-alkynyl-substituted carbonyl compounds, and alkynes react to give 1-iodonaphthalene derivatives featuring interesting substitution patterns. The reaction with alkenes instead of acetylenes affords related naphthyl ketone derivatives. These two metal-free processes are conducted at room temperature and furnish products in a regioselective manner.
The Reaction ofo-Alkynylarene and Heteroarene Carboxaldehyde Derivatives with Iodonium Ions and Nucleophiles: A Versatile and Regioselective Synthesis of 1H-Isochromene, Naphthalene, Indole, Benzofuran, and Benzothiophene Compounds
作者:José Barluenga、Henar Vázquez-Villa、Isabel Merino、Alfredo Ballesteros、José M. González
DOI:10.1002/chem.200501505
日期:2006.7.24
adapted to accomplish the synthesis of indole, benzofuran, and benzothiophenederivatives (23, 27, and 28, respectively). The three patterns of reactivity observed for the o-alkynylbenzaldehyde derivatives with IPy(2)BF(4) stem from a common iodinated isobenzopyrylium ion intermediate, A, that evolves in a different way depending on the nucleophile present in the reaction medium. A mechanism is proposed
Cu(OTf)(2) and 1 equiv of a Brønstedacid, such as CF(2)HCO(2)H, in (CH(2)Cl)(2) at 100 degrees C, the decarbonylated naphthalene products 5 were obtained in high yields. Similarly, the Cu(OTf)(2)-H(2)O-promoted reaction of the enynals 7 with an alkyne 2 afforded the corresponding [4+2] benzannulation products, decarbonylated benzene derivatives 8, in good yields. Both AuX(3)- and Cu(OTf)(2)-catalyzed
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
o-alkynylbenzaldehydes and alkynes to yield 1-naphthyl aryl ketones is reported. The reaction conditions are mild, metal-free, and do not require pretreatment/protection of the substrates. We found that aryl propargyl alcohols were very effective substrates for this reaction, compared with other alkynes. Studies on the reaction scope, monitoring the reaction progress by 1H NMR, and theoretical calculations suggest
报道了溴三甲基硅烷促进邻炔基苯甲醛和炔烃的苯并环化以产生 1-萘基芳基酮。反应条件温和,不含金属,不需要对基材进行预处理/保护。我们发现,与其他炔烃相比,芳基炔丙醇是该反应非常有效的底物。反应范围研究、 1 H NMR监测反应进程和理论计算表明,异苯并吡啶离子是关键的反应中间体。