Yb(OTf)<sub>3</sub>-Catalyzed Reactions of 5-Alkylidene Meldrum's Acids with Phenols: One-Pot Assembly of 3,4-Dihydrocoumarins, 4-Chromanones, Coumarins, and Chromones
作者:Eric Fillion、Aaron M. Dumas、Bryan A. Kuropatwa、Neil R. Malhotra、Tamsyn C. Sitler
DOI:10.1021/jo052000t
日期:2006.1.1
Yb(OTf)3-catalyzed annulation reactions of phenols with 5-alkylidene Meldrum's acids enabled the synthesis of structurally diverse heterocycles in high isolated yields. A series of 4-substituted 3,4-dihydrocoumarins, 2,2-disubstituted 4-chromanones, coumarins, and 2-substituted chromones were readily and efficiently assembled, including the naturally occurring coumarins citropten, scoparone, and ayapin
Yb(OTf)3催化的苯酚与5-亚烷基Meldrum酸的环化反应能够以高分离产率合成结构多样的杂环。一系列4-取代的3,4-二氢香豆素,2,2-二取代的4-发色酮,香豆素和2-取代的色酮容易而有效地组装,包括天然存在的香豆素香茅素,香柏酮和阿平。将苯酚添加到双亲电子性5-亚烷基Meldrum的酸中,通过两种不同的多键形成方式进行:弗里德-克拉夫特C-烷基化/ O-酰化和弗里德-克拉夫特C-酰化/ O-烷基化。催化环化反应的区域选择性由亚烷基部分上的取代度控制。