铁催化2-烯基氮杂芳烃的绿色合成

Iron-Catalyzed Green Synthesis of 2-Alkenylazaarenes

以廉价、低毒的醋酸亚铁为催化剂,在三氟乙酸助催化下,2-甲基氮杂芳烃与芳香醛经过加成与脱水反应,直接选择性合成具有生物活性的反式2-烯基氮杂芳烃化合物,水是唯一副产物.该合成方法催化剂用量少,后处理方便,产率高,选择性高,底物适用范围广.治疗哮喘药顺尔丁中间体(E)-3-[2-(7-氯-2-喹啉基)乙烯基]苯甲醛(3v)的克级合成展现了该方法的应用前景.

A straightforward and selective synthesis of bioactive trans-2-alkenylazaarenes has been achieved via cheap and nontoxic iron（II） acetate catalyzed addition and dehydration reactions of 2-methylazaarenes and aromatic aldehydes in the presence of catalytic amount of trifluoroacetic acid with water as the only byproduct. The low catalyst loading, convenience, good yield, high selectivity, as well as the broad substrate scope make this protocol very practical. The practical potential was also demonstrated by gram-scale synthesis of （E）-3-[2-（7-chloro-2-quinolinyl）ethenyl]benzaldehyde （3v）, an intermediate of Singulair.