Oxa-Pictet–Spengler reaction in water. Synthesis of some (±)-1-aryl-6,7-dimethoxyisochromans
作者:Aamer Saeed
DOI:10.1016/j.cclet.2009.11.009
日期:2010.3
Abstract An acid catalyzed oxa-Pictet–Spengler reaction ‘on water’ leading to the synthesis of a variety of 1-aryl-6,7-dimethoxyisochromans is described. The aqueous chemistry is a much cleaner, efficient, cheaper and simple method for synthesis. The scope of reactions was extended to thia-Pictet–Spengler reaction to afford the some isothiochromans.
Structurally Diverse α-Substituted Benzopyran Synthesis through a Practical Metal-Free C(sp<sup>3</sup>)–H Functionalization
作者:Wenfang Chen、Zhiyu Xie、Hongbo Zheng、Hongxiang Lou、Lei Liu
DOI:10.1021/ol503004a
日期:2014.11.21
A trityl ion-mediated practical C–H functionalization of a variety of benzopyrans with a wide range of nucleophiles (organoboranes and C–H molecules) at ambient temperature has been disclosed. The metal-free reaction has an excellent functional group tolerance and high chemoselectivity and displays a broad scope with respect to both benzopyran and nucleophile partners, efficiently affording a collection
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
Zeolite-catalyzed simple synthesis of isochromans via the oxa-Pictet–Spengler reaction
作者:Adrienn Hegedüs、Zoltán Hell
DOI:10.1039/b601314g
日期:——
The modified small pore size zeolite E4a has been found to be an efficient catalyst for the synthesis of isochromans via the oxa-PictetâSpengler reaction. This method is simple, cheap, environmentally-friendly and gives the isochromans in high yield.
Cross-dehydrogenative coupling of secondary benzylic ethers with indoles and pyrroles
作者:Min Cao、Ying Mao、Jiancheng Huang、Yudao Ma、Lei Liu
DOI:10.1016/j.tetlet.2019.03.032
日期:2019.4
Current studies on cross-dehydrogenative coupling of benzylic ethers for new C–C bond construction predominantly focus on primary ether moieties. Oxidative cross-coupling of secondary benzylic ethers remains elusive. Herein, we describe the first cross-dehydrogenative coupling of secondary benzylic ethers with indoles and pyrroles for tertiary ether construction. A broad range of α-aryl substituted