ABSTRACT
A carbon-supported copper nanoparticle (Cu-NP) with high catalytic activity for the synthesis of diaryl sulfones is reported. For the first time, this Cu-NP is proved to be able to effectively promote the reaction of arylboronic acids and arylsulfonyl hydrazides to generate diaryl sulfones at room temperature. The reaction shows excellent substrate universality, and substrates with different substituents can undergo the reaction smoothly, leading to the desired products in good yields. The Cu-NP is found to be made of low valence Cu based on XRD. Hence, the reaction catalyzed by the Cu-NP is believed to involve a Cu-mediated organometallic cycle.
ABSTRACT
This article gives a short review on the visible-light promoted synthesis of α-functionalized ketones from alkenes. Various α-functionalized ketones, including α-halo, sulfinyl/sulfonyl, aryl, azido and thiocyanato ketones can be synthesized from the reaction of alkenes with different radical species generated by visible-light catalysis. These transformations typically use dioxygen as the terminal oxidant and do not require a transition metal to activate the double bond, which is quite different from the transition-metal catalysed reactions (Wacker oxidation or hydroformylation).
ABSTRACT
A practical method has been developed for the conversion of alkenes to ß-keto/hydroxyl sulfones by their reaction with sulfonyl hydrazides under metal-free conditions. This reaction proceeds through the oxidative addition of alkenes by sulfonyl radicals that are generated by visible-light induced oxidation of sulfonyl hydrazides. Notaly the reaction uses O2 as the terminal oxidant, instead of metal catalysts or oxidants like TBHP, leading to H2O and N2 as the clean by-products. The key features of this reaction include readily available reagents, mild reaction conditions and broad substrate scope.