Arylation and Vinylation of α-Diazocarbonyl Compounds with Boroxines
摘要:
An alternative approach for alpha-arylation and alpha-vinylation of carbonyl compounds is described: reaction between aryl- or vinylboroxines with alpha-diazocarbonyl compounds leads to the formation of alpha-arylated or alpha-vinylated carbonyl compounds under mild conditions.
Selective α-Methylation of Aryl Ketones Using Quaternary Ammonium Salts as Solid Methylating Agents
作者:Johanna Templ、Michael Schnürch
DOI:10.1021/acs.joc.1c03158
日期:2022.3.18
We describe the use of phenyl trimethylammonium iodide (PhMe3NI) as an alternative methylatingagent for introducing a CH3 group in α-position to a carbonyl group. Compared to conventional methylatingagents, quaternary ammonium salts have the advantages of being nonvolatile, noncancerogenic, and easy-to-handle solids. This regioselective method is characterized by ease of operational setup, use of
photocatalytic metal-free cross-coupling of benzylic and aldehydic C–H bonds by synergistic catalysis of organophotocatalyst 4CzIPN and a thiol, which affords the corresponding α-aryl ketones in acceptable yields along with hydrogen evolution. The mechanistic investigation indicates a radical–radical coupling to give an intermediary alcohol, followed by an acceptorless alcohol dehydrogenation.