Aerobic epoxidation of tertiary allylic alcohols remains a significant challenge. Reported here is an efficient and highly chemoselective copper‐catalyzed epoxidation and semipinacol rearrangement reaction of tertiary allylic alcohols with molecular oxygen. The solvent 1,4‐dioxane activates dioxygen, thereby precluding the addition of a sacrificial reductant.
Unexpected Copper-Catalyzed Aerobic Oxidative Cleavage of C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Bond of Glycol Ethers
作者:Zhong-Quan Liu、Lixing Zhao、Xiaojie Shang、Zili Cui
DOI:10.1021/ol301220s
日期:2012.6.15
An unexpected Cu-catalyzed oxidative cleavage of the C(sp(3))-C(sp(3)) bond in glycol ethers by using air or molecular oxygen as the terminal stoichiometric oxidant is demonstrated. As a result, the corresponding alpha-acyloxy ethers and formates of 1,2-ethanediol are formed by direct coupling of carboxylic acids and aldehydes with glycol ethers under the reaction conditions. This method represents the first example of Cu-catalyzed aerobic cleavage of saturated C-C bond in ethers.
Ultrasound-promoted synthesis of a copper–iron-based catalyst for the microwave-assisted acyloxylation of 1,4-dioxane and cyclohexene
作者:Pablo Macías-Benítez、Alfonso Sierra-Padilla、M. Pilar Yeste、José María Palacios-Santander、Laura Cubillana-Aguilera、José M. Gatica、Hilario Vidal、Francisco M. Guerra、F. Javier Moreno-Dorado
DOI:10.1039/d2ob02117j
日期:——
A copper–iron-based catalyst has been prepared by a low-temperature co-precipitation and sonication method. The use of high-energy ultrasound reduces the time required for the preparation process from one workweek to one day with respect to the catalysts obtained by conventional coprecipitation and thermal treatment methods. The resulting material has been characterized at compositional, textural, structural