Shiyu Guo

I2-promoted aerobic oxidative coupling of acetophenes with amines under metal-free conditions: facile access to α-ketoamides

A novel and efficient I2-promoted oxidative coupling of acetophenes with amines to α-ketoamides is presented, which employs O2 as an environmentally friendly oxidant under metal-free conditions. Based on a series of control experiments and radical trapping experiments, plausible reaction mechanism was proposed and iminium ion was identified as a significant intermediate in this process. This methodology is a feasible, mild approach to α-ketoamides in good yields.

A two-step continuous synthesis of α-ketoamides and α-amino ketones from 2° benzylic alcohols using hydrogen peroxide as an economic and benign oxidant

A practical two-step synthesis of α-ketoamides and α-amino ketones via direct oxidative coupling between 2° benzylic alcohols and amines was developed. Hydrogen peroxide, an economic and environmentally friendly oxidant, was used, and a metal catalyst was unnecessary. Moreover, the continuous-flow technique was employed to increase the functional group tolerance, efficiency and safety.

Metal-free oxidative esterification of acetophenones with alcohols: a facile one-pot approach to α-ketoesters

A novel and efficient oxidative esterification method for the synthesis of α-ketoesters has been developed under mild and environmentally benign conditions, which is a facile one-pot approach to α-ketoesters from commercially available acetophenones with alcohols, especially under metal-free conditions, with broad substrate scope. A possible mechanism is proposed on the basis of a series of control experiments and DMSO18 isotopic labelling experiments.

Highly practical sodium(I)/azobenzene catalyst system for aerobic oxidation of benzylic alcohols

An economic, environmental and practical aerobic oxidation of benzylic alcohols and hetero aryl alcohols to the corresponding carbonyl compounds with good substrate scope is disclosed for the first time. Good to excellent yields were obtained by employing economic and commercially available sodium bromide and a catalytic amount of azobenzene under metal-free and ligand-free conditions. Moreover, aldehydes and acids, the oxidation products of benzylic 1° alcohols, could be obtained using sodium bromide and sodium hydroxide as the co-catalyst respectively in high yields.

Microfluidic synthesis of α-ketoesters via oxidative coupling of acetophenones with alcohols under metal-free conditions

An efficient and novel method for the synthesis of α-ketoesters has been developed via oxidative coupling of acetophenones with alcohols under TBHP/I2/DBU conditions in a microfluidic chip reactor, which has a wide substrate scope, uses a lower dosage of iodine and affords higher product yields in only a few seconds. Moreover, a scale-up continuous flow system is also feasible and the plausible reaction mechanism has been proposed based on a series of control experiments.