Synthesis of Benzofurans with Remote Bromide Functionality by Domino “Ring-Cleavage-Deprotection-Cyclization” Reactions of 2-Alkylidenetetrahydrofurans with Boron Tribromide
作者:Esen Bellur、Peter Langer
DOI:10.1021/jo051079z
日期:2005.9.1
Bromination and subsequent Suzuki reactions of 2-alkylidenetetrahydrofurans, readily available by [3+2] cyclizations, afforded 1‘-(2‘ ‘-methoxyphenyl)-2-alkylidenetetrahydrofurans. Treatment of the latter with boron tribromide and subsequent addition of water resulted in the chemoselective formation of functionalized benzofurans containing a remote bromide functionality. The products are formed by
通过[3 + 2]环化容易获得的2-亚烷基四氢呋喃的溴化反应和随后的Suzuki反应,得到1'-(2''-甲氧基苯基)-2-亚烷基四氢呋喃。用三溴化硼处理后者并随后加水导致化学选择性地形成官能化的苯并呋喃,该苯并呋喃具有较远的溴化物官能度。产品是通过新的多米诺骨牌“环断裂-去保护-环化”反应形成的。通过“环裂解-脱保护-环-封闭-内酯化”反应,加入叔丁醇钾的水溶液而不是水,得到了茶氨酸的饱和类似物。