Organic synthesis via magnetic attraction: benign and sustainable protocols using magnetic nanoferrites
作者:R. B. Nasir Baig、Rajender S. Varma
DOI:10.1039/c2gc36455g
日期:——
Magnetic nano-catalysts have been prepared using simple modification of iron ferrites. The nm size range of these particles facilitates the catalysis process, as an increased surface area is available for the reaction; the easy separation of the catalysts by an external magnet and their recovery and reuse are additional beneficial attributes. Glutathione bearing nano-ferrites have been used as organocatalysts for the Paal–Knorr reaction and homocoupling of boronic acids. Nanoferrites, post-synthetically modified by ligands, were used to immobilize nanometals (Cu, Pd, Ru, etc.) which enabled the development of efficient, sustainable and green procedures for azide–alkynes-cycloaddition (AAC) reactions, C–S coupling, O-allylation of phenol, Heck-type reactions and hydration of nitriles.
of plant, fungal, and bacterial origin. In this paper an improved method for the chemical synthesis of differently substituted chromanes is described. Substituted 2H-1-benzopyrans have been synthesized in good to excellent yields (52–81%) by treatment of 3,3-dimethylallyl and propenylbenzene ethers of differently substituted phenols with phenylselenyl chloride.
苯并二氢吡喃核心在自然界中广泛存在,是植物,真菌和细菌来源的许多次级代谢产物的一部分。在本文中,描述了一种化学合成不同取代的苯并二氢吡喃的改良方法。通过用苯基硒烯基氯处理不同取代的苯酚的3,3-二甲基烯丙基和丙烯基苯醚,可以很好地合成优良的产率(52-81%)的2 H -1-苯并吡喃。
Asymmetric Radical Oxyboration of <i>β</i>‐Substituted Styrenes via Late‐Stage Stereomutation
developed, providing a convenient and efficient approach to enantioenriched trans-1,2-difunctionalized products. The key of the success is the development of a formal late-stage stereomutation strategy, which could enable chiral cis-isomers to be converted into trans-isomer, thus achieving high diastereocontrol.
Low‐Valent Cobalt‐Catalyzed Deprotection of Allyloxyarenes
作者:Branislav Kokić、Života Selaković、Andrea M. Nikolić、Ana Andrijević、Boban Anđelković、Vladimir Ajdačić、Igor M. Opsenica
DOI:10.1002/ejoc.202201112
日期:2022.11.18
AbstractHerein, we report a low‐valent cobalt‐catalyzed deprotection of allyloxyarenes. The method displays a broad substrate scope and good functional group tolerance, granting its utilization on more complex substrates, includingO‐allylated derivatives of natural products and drugs. Based on comprehensive experiments, a plausible mechanistic pathway for the low‐valent cobalt‐catalyzedO‐deallylation of allyloxyarenes is proposed.
O-Allylation of phenols with allylic acetates in aqueous media using a magnetically separable catalytic system
作者:Amit Saha、John Leazer、Rajender S. Varma
DOI:10.1039/c1gc16174a
日期:——
Allylic ethers were synthesized in water using magnetically recoverable heterogeneous Pd catalystvia O-allylation of phenols with allylic acetates under ambient conditions. The aqueous reaction medium, easy recovery of the catalyst using an external magnet, efficient recycling, and the high stability of the catalyst renders the protocol economic and sustainable.