Manganese-Catalyzed Stereospecific Hydroxymethylation of Alkyl Tosylates
作者:Hannah Shenouda、Erik J. Alexanian
DOI:10.1021/acs.orglett.9b03706
日期:2019.11.15
The development of a stereospecific hydroxymethylation of alkyl tosylates using an inexpensive, first-row catalyst is described. The transformation proceeds under mild conditions with low pressure to deliver homologated alcohols as products. Chiral, nonracemic β-branched primary alcohols are obtained with high enantiospecificity from easily accessed secondary alkyl substrates. Simple modification of
Ytterbium Triflate Mediated Selective Deprotection of Acetates
作者:G. V. M. Sharma、A. Ilangovan
DOI:10.1055/s-1999-2975
日期:1999.12
Ytterbium triflate mediated selective deprotection of acetates in isopropyl alcohol at reflux temperature is reported. Unlike hafnium triflate, under the present reaction conditions aryl acetates also undergo deacetylation instead of Fries migration.
Mild and Chemoselective Deacetylation Method Using a Catalytic Amount of Acetyl Chloride in Methanol
作者:B. Kim、Chang-Eun Yeom、So Lee、Young Kim
DOI:10.1055/s-2005-869838
日期:——
Efficient deacetylation of alcohol acetates under mild acidic conditions was accomplished with a catalytic amount of acetyl chloride in methanol. Acetates of various primary, secondary, aromatic and sugar alcohols were successfully deprotected. Highly chemoselective removal of acetyl groups in presence of other commonly employed esters was also achieved in excellent yields. The reactivity of this transesterification-mediated deacetylation was found to be directly dependent upon the electronic and steric nature of the acetates.
Oxidative photoredox catalysis: mild and selective deprotection of PMB ethers mediated by visible light
作者:Joseph W. Tucker、Jagan M. R. Narayanam、Pinkey S. Shah、Corey R. J. Stephenson
DOI:10.1039/c1cc10827a
日期:——
Herein we report an advancement in the application of visible light photoredox catalysts in the oxidation of electron-rich arenes resulting in the selectivedeprotection of para-methoxybenzyl (PMB) ethers. This method is highlighted by excellent functional group tolerance, protecting group orthogonality, mild reaction conditions and avoidance of stoichiometric redox byproducts.
Oxidative Deprotection of <i>p</i>-Methoxybenzyl Ethers via Metal-Free Photoredox Catalysis
作者:Deok Kyun Ahn、Young Woo Kang、Sang Kook Woo
DOI:10.1021/acs.joc.8b02951
日期:2019.3.15
method for p-methoxybenzyl (PMB) ethers using a metal-free visible light photoredox catalyst and air and ammonium persulfate as the terminaloxidants is presented. Various functional groups and protectinggroups were tolerated in the developed method to achieve good to excellent yields in short reaction times. Significantly, the developed method was compatible with PMB ethers derived from primary, secondary