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.
example of the direct halosulfenylation of benzo[b]furans with commercially available disulfides and N-halosuccinimides has been achieved, providing an efficient metal-free synthetic pathway to access diverse 3-halo-2-thiobenzo[b]furans in moderate to excellent yields. In particular, a halogen (e.g., bromo or iodo) substituent on the benzo[b]furan ring is amenable for further synthetic elaborations
苯并[ b ]呋喃与市售二硫化物和N-卤代琥珀酰亚胺直接卤代亚磺酰化的第一个例子已经实现,它提供了一种有效的无金属合成途径,以中等到中等的程度使用各种3-卤-2-硫代苯并[ b ]呋喃。优异的产量。特别地,苯并[ b ]呋喃环上的卤素(例如,溴或碘)取代基适于进一步合成合成,从而扩大了产物的多样性。