Electrophilic Cyclization of 2-Chalcogenealkynylanisoles: Versatile Access to 2-Chalcogen-benzo[b]furans
摘要:
An efficient synthesis of 2-chalcogen-3-substituted-benzo[b]furan compounds has been accomplished via electrophilic cyclization reaction of 2-chalcogenealkynyl anisoles using I-2, ICl, Br-2 and PhSeBr as electrophile sources. The product distributions were strongly dependent on the nature of substituents in the aromatic ring of anisole and on the chalcogen atom directly bonded to the triple bond. The 2-chalcogen-3-iodo-benzo[b]furans obtained smoothly underwent conversion to more complex structures of benzo[b]furan derivatives via palladium- or copper-catalyzed cross-coupling reaction with thiols, diphenyl diselenides, and zincates.
通过钯催化的3-碘-2-(甲基硫烷基)苯并[ b ]呋喃与各种末端炔的交叉偶联,可以在温和的反应条件下轻松制备3-炔基-2-(甲基硫烷基)苯并[ b ]呋喃。该反应用炔丙醇,受保护的炔丙醇以及烷基和芳基末端炔烃进行。另外,使用氢碲化反应容易地将获得的3-炔基苯并[ b ]呋喃转化为更复杂的产物,这以良好的产率提供了所需的乙烯基碲化物。此外,使用铜催化的均偶联反应,我们能够以良好的收率将3-炔基苯并[ b ]呋喃转化为对称的二炔。 钯-Sonogashira交叉偶联-呋喃-炔烃-催化