Arylhydroxylamines were used in the nitroso Diels-Alder reaction to generate in-situ nitrosoarens under visible light catalytic aerobic conditions. Mixing a solution of aryl- or heteroaryl-hydroxylamines with conjuguated dienes in the presence of a catalytic amount of Ru(bpy)3Cl2 afforded, under an oxygen atmosphere, the 3,6-dihydro-1,2-oxazines in good yields.
Molecular Design of a Chiral Brønsted Acid with Two Different Acidic Sites: Regio-, Diastereo-, and Enantioselective Hetero-Diels–Alder Reaction of Azopyridinecarboxylate with Amidodienes Catalyzed by Chiral Carboxylic Acid–Monophosphoric Acid
A chiral Brønsted acid containing two different acidic sites, chiral carboxylic acid-monophosphoric acid 1a, was designed to be a new and effective concept in catalytic asymmetric hetero-Diels-Alder reactions of azopyridinecarboxylate with amidodienes. The multipoint hydrogen-bonding interactions among the carboxylic acid, monophosphoric acid, azopyridinecarboxylate, and amidodiene achieved high catalytic