Synthesis of isochromans via Fe(OTf)2-catalyzed Oxa-Pictet–Spengler cyclization
作者:Jimei Zhou、Chao Wang、Dong Xue、Weijun Tang、Jianliang Xiao、Chaoqun Li
DOI:10.1016/j.tet.2018.10.028
日期:2018.12
Fe(OTf)2 has been found to be an efficient catalyst for the Oxa-Pictet–Spengler cyclization reaction leading to isochromans. A series of substituted isochromans were obtained with good to excellent isolated yields by coupling β-arylethanols with aldehydes or ketals under the catalysis of 1 mol% of Fe(OTf)2 at 70 °C. Using a cheap, less-toxic catalyst with water as the only byproduct, this iron-catalyzed
The oxa-Pictet-Spengler reaction with various aldehydes and -arylethanol yields 1-substituted-isochromans in the presence of bismuth triflate as catalyst in good yields. The method was extended to O,O-acetals to afford the corresponding 1,1-disubstituted-isochromans in good yields. These studies also provide insights into the catalytic role of triflic acid generated upon hydrolysis of Bi(OTf)3 by residual water. The low toxicity and easy handling of Bi(OTf)3 by comparison with triflic acid make these procedures an attractive method to provide isochromans in good to excellent yields.
一种催化氧化异色满制备2-羟乙基苯基酮的 方法
申请人:西安石油大学
公开号:CN112321401B
公开(公告)日:2023-04-28
Heteropolyacid ionic liquid heterogeneously catalyzed synthesis of isochromans <i>via</i> oxa-Pictet–Spengler cyclization in dimethyl carbonate
作者:Guoping Yang、Ke Li、Kai Zeng、Yijin Li、Tao Yu、Yufeng Liu
DOI:10.1039/d1ra01004b
日期:——
3-ethyl-5-(2-hydroxyethyl)-4-methylthiazol-3-ium (HEMT), i.e., [HEMTH]H2[PMo12O40] was prepared. Oxa-Pictet–Spengler cyclization of arylethanols and aldehydes were catalyzed to afford various substituted isochromans in moderate conditions with excellent yields using dimethyl carbonate (DMC) as a green solvent. Furthermore, this protocol was applicable in a gram-scale reaction, and the catalyst could