2,3,4- or 2,3,5-Trisubstituted Furans: Catalyst-Controlled Highly Regioselective Ring-Opening Cycloisomerization Reaction of Cyclopropenyl Ketones
作者:Shengming Ma、Junliang Zhang
DOI:10.1021/ja036616g
日期:2003.10.1
furans were highly regioselectively formed from the cycloisomerization reaction of the same starting cyclopropenes 1 via the subtle choice of the transition metal halides. Under the catalysis of 5 mol % PdCl2(CH3CN)2, 2,3,5-trisubstituted furans 2 were given in 50-88% yields with 95-99% regioselectivities, while 2,3,4-trisubstituted furans 3 were formed in 78-96% yields with 99% regioselectivities under
2,3,4- 或 2,3,5- 三取代呋喃通过过渡金属卤化物的微妙选择,由相同起始环丙烯 1 的环异构化反应高度区域选择性地形成。在 5 mol% PdCl2(CH3CN)2 的催化下,2,3,5-三取代呋喃 2 的产率为 50-88%,区域选择性为 95-99%,而 2,3,4-三取代呋喃 3 则在在 5 mol% CuI 的催化下,78-96% 的产率和 99% 的区域选择性。