[4+2] Cycloadditions between 2-pyrones and benzyne. Application to the synthesis of binaphthyls
作者:Sonia Escudero、Dolores Pérez、Enrique Guitián、Luis Castedo
DOI:10.1016/s0040-4039(97)01176-3
日期:1997.7
Cycloaddition of benzyne to 2-pyrones affords the corresponding naphthalene derivatives, the intermediate bicyclic adduct not being detected. Benzopyrones do not react with benzyne under similar conditions probably because this would require the fused aromatic ring to lose aromaticity in the Diels-Alder transition state, which is therefore destabilized. 4-Bromo-2-naphthoic acid methyl ester (obtained by cycloaddition
苯并炔与2-吡喃酮的环加成反应得到相应的萘衍生物,未检测到中间体双环加合物。在相似的条件下,苯并吡喃酮不会与苯并react反应,可能是因为这将要求稠合的芳环在Diels-Alder过渡态下失去芳香性,因此不稳定。可以通过Ni介导的方法将4-溴-2-萘甲酸甲酯(通过将苯甲醛环加成至3-溴5-羧甲基吡喃-2-酮而获得)转化为3,3'-二羧甲基-1,1'-联萘基二聚化。