Hydroxy compounds readily add to 3,4-dihydro-2H-pyran under neutral conditions in the presence of a catalytic amount of 2,3-dichloro-5,6-dicyano-p-benzoquinone, to give high yields of the corresponding tetrahydropyranyl ethers.
Diphenylamine-Terephthalaldehyde Resin <i>p</i>-Toluenesulfonate (DTRT) as an Efficient Catalyst for Tetrahydropyranylation, Deprotection of Tetrahydropyranyl and Silyl Ethers, Esterification, and Transesterification
作者:Kiyoshi Tanemura、Tsuneo Suzuki
DOI:10.1080/00304948.2016.1127103
日期:2016.1.2
employed in organic synthesis because of simplified work-up procedure, use of the recycled catalysts, and minimized corrosion of metallic reaction vessels. Although several strongly acidic resin catalysts such as Amberlyst 15, Dowex 50, and Nafion NR50 have been used as catalysts, they are not suitable for use with acid-sensitive compounds. The few commercially available weakly acidic resins such as poly(4-vinylpyridinium
Aniline–terephthalaldehyde resin p-toluenesulfonic acid (ATRT) salt as efficient mild polymeric solid acid catalyst
作者:Kiyoshi Tanemura、Tsuneo Suzuki
DOI:10.1016/j.tetlet.2013.09.137
日期:2013.12
Aniline-terephthalaldehyde resin p-toluenesulfonic acid (ATRT) salt was easily prepared by the reaction of aniline with 1.25 equiv of terephthalaldehyde in the presence of 1.0 equiv of p-toluenesulfonic acid at 75 degrees C for 24 h in EtOH. ATRT efficiently catalyzed the tetrahydropyranylation of alcohols and deprotection of tetrahydropyranyl (THP), triethylsilyl (TES), and tert-butyldimethylsilyl (TBDMS) ethers. Deprotection of dodecyl THP ether and dodecyl TBDMS ether catalyzed by ATRT proceeded faster than those by pyridinium p-toluenesulfonate (PPTS). ATRT was reused without significant loss of activities. (C) 2013 Elsevier Ltd. All rights reserved.