An epimerization–lactamization cascade of functionalized (2S,4R)-4-aminoproline methyl esters is developed and applied in synthesizing (1R,4R)-2,5-diazabicyclo[2.2.1]heptane (DBH) derivatives.

In catalytic reactions, trace amounts of promoters can make up for the low activity of a catalyst and significantly affect the physicochemical properties of the catalyst. Exploring a simple and efficient composite Cu-based catalyst is essential to the Rochow-Müller reaction. In this work, monodisperse, a hydrangea-like 0.3Zn-0.15Sn/CuO composite catalyst in the Rochow-Müller reaction. The composite was synthesized via a microwave-assisted liquid-phase synergistic impregnation method in which Sn and Zn were used to dope the CuO surface to create strong Si interaction points. A significant increase in the catalytic activity of CuO was observed after Sn and Zn doping, attributed to the rearrangement of charges on the CuO surface and increase in the Cu atom's core electron density. This work provided a novel and efficient method for preparing efficient Cu-based catalysts for the Rochow-Müller reaction.

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