Chemoselective Formation of Unsymmetrically Substituted Ethers from Catalytic Reductive Coupling of Aldehydes and Ketones with Alcohols in Aqueous Solution
作者:Nishantha Kalutharage、Chae S. Yi
DOI:10.1021/acs.orglett.5b00553
日期:2015.4.3
A well-defined cationic Ru–H complex catalyzes reductive etherification of aldehydes and ketones with alcohols. The catalytic method employs environmentally benign water as the solvent and cheaply available molecular hydrogen as the reducing agent to afford unsymmetrical ethers in a highly chemoselective manner.
a triple catalysis consisting of photoredox, cobalt, and Brønsted acid catalysts under visible light irradiation. The triple catalysis realizes three key elementary steps in a single catalytic cycle: (1) Co(III) hydride generation by photochemical reduction of Co(II) followed by protonation, (2) metal hydride hydrogen atom transfer (MHAT) of alkenes by Co(III) hydride, and (3) oxidation of the alkyl
我们展示了在可见光照射下通过由光氧化还原、钴和布朗斯台德酸催化剂组成的三重催化,使用醇对未活化烯烃进行马尔科夫尼科夫加氢烷氧基化。三重催化在单个催化循环中实现了三个关键的基本步骤:(1)通过光化学还原 Co(II)然后质子化生成 Co(III)氢化物,(2)通过 Co 对烯烃的金属氢化物氢原子转移(MHAT) (III)氢化物,和(3)烷基Co(III)配合物氧化成烷基Co(IV)。三种催化剂对质子和电子的精确控制可以消除传统方法中所需的强酸和外部还原剂/氧化剂。
Transition metal-free approach for late-stage benzylic C(sp<sup>3</sup>)–H etherifications and esterifications
作者:Yu Zhang、Prakash Kumar Sahoo、Peng Ren、Yuman Qin、Robin Cauwenbergh、Philippe Nimmegeers、Gandhi SivaRaman、Steven Van Passel、Andrea Guidetti、Shoubhik Das
DOI:10.1039/d2cc02661a
日期:——
We report a transitionmetal-freeapproach for the regioselective functionalization of benzylic C(sp3)–H bonds using alcohols and carboxylic acids as the nucleophiles. This straightforward and general route has provided various benzylic ethers and esters, including twelve pharmaceutically relevant compounds.