Photo-on-Demand Synthesis of Vilsmeier Reagents with Chloroform and Their Applications to One-Pot Organic Syntheses

The Vilsmeier reagent (VR), first reported a century ago, is a versatile reagent in a variety of organic reactions. It is used extensively in formylation reactions. However, the synthesis of VR generally requires highly toxic and corrosive reagents such as POCl₃, SOCl₂, or COCl₂. In this study, we found that VR is readily obtained from a CHCl₃ solution containing N,N-dimethylformamide or N,N-dimethylacetamide upon photo-irradiation under O₂ bubbling. The corresponding Vilsmeier reagents were obtained in high yields with the generation of gaseous HCl and CO₂ as byproducts to allow their isolations as crystalline solid products amenable to analysis by X-ray crystallography. With the advantage of using CHCl₃, which bifunctionally serves as a reactant and a solvent, this photo-on-demand VR synthesis is available for one-pot syntheses of aldehydes, acid chlorides, formates, ketones, esters, and amides.

Palladium-Catalyzed Multistep Tandem Carbonylation/N-Dealkylation/Carbonylation Reaction: Access to Isatoic Anhydrides

A novel and efficient synthesis of isatoic anhydride derivatives was developed via palladium-catalyzed multistep tandem carbonylation/N-dealkylation/carbonylation reaction with alkyl as the leaving group and tertiary anilines as nitrogen nucleophiles. This approach features good functional group compatibility and readily available starting materials. Furthermore, it provided a convenient approach for the synthesis of biologically and medicinally useful evodiamine.