selenium, sulfur and oxygen nucleophiles we observed that the nucleophilicity and steric effects of the competing functional groups were determinant factors for the selectivity of the cyclization. The benzo[b]chalcogenopheno[2,3‐d]furans had absorptions in the UV region (300–350 nm range) with molar absorptivity coefficient values ascribed to spin and symmetry allowed π–π* electronic transitions. An emission
丁基[2-(phenylbuta-1,3-二炔基)苯基]
硫属元素的双分子5-内-dig环化已用于选择性制备苯并[ b ]
硫属元素毒素[2,3- d]
呋喃。研究了几个反应参数以确定最佳反应条件,我们观察到丁基[2-(苯基丁亚-1,3-二炔基)苯基]
硫族元素(0.25 mmol)与六
水合氯化铁(III)(2.0当量)的反应
二氯甲烷回流中的二有机基二
硒化物(1.75当量)最适合以35-89%的收率得到产品。这些标准反应条件与底物中的许多官能团相容,例如甲基,
氯,
氟,甲氧基和杂芳基。该方案对于二有机基二
硒化物也有效,但对二有机基二
硫化物和二
碲化物无效。在
硒的竞争中
硫和氧亲核试剂,我们观察到竞争性官能团的亲核活性和空间效应是环化选择性的决定性因素。苯并[b ]
硫代
苯并呋喃[2,3- d ]
呋喃在紫外区(300-350 nm范围)具有吸收,摩尔吸收系数值归因于自旋,对称性允许π-π*电子跃迁。紫色区域(380–440