dichloromethane in the presence of triethylamine to give a wide variety of functionalized benzo[c]coumarin derivatives in good yields. This new annulation reaction presumably proceeds by a tandem intermolecular Michael addition and subsequent intramolecular condensation between an intermediate enolate anion and cyano group. In the case of 3-cyano-4-methylcoumarin and 2-(trifluoromethyl)chromones activated
2-(多氟烷基)
色酮与4-烷基-3-
氰基
香豆素在
二氯甲烷中,在
三乙胺的存在下反应,以高收率得到各种官能化的苯并[ c ]
香豆素衍
生物。这种新的环化反应大概是通过串联分子间迈克尔加成反应以及随后的中间烯醇式阴离子和
氰基之间的分子内缩合而进行的。在3-
氰基-4-甲基
香豆素和2-(三
氟甲基)
色酮被两个吸电子取代基激活的情况下,分离出三个无环中间体,并提出了可能的反应机理。