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.
α-Acetyl- and α-Cyanovinyl 2,4-Dinitrophenyl Carboxylate as Useful Ketene Equivalents for the Diels-Alder Reaction
作者:David MaGee、May Lee
DOI:10.1055/s-1997-5775
日期:1997.7
Two ketene equivalents (5 and 35) have been developed for use in the Diels-Alder reaction. These dienophiles exhibit a marked increase in reactivity in comparison with the more conventional acetoxyacrylonitrile. Conversions of the cycloadducts to the requisite ketones occurs under mild, and moderate to high yielding conditions.
Chiral pyridinium phosphoramide 1·HX was designed to be a new class of chiral Brønsted acid catalyst in which both the pyridinium proton and the adjacent imide-like proton activated by the electron-withdrawing pyridinium moiety could work cooperatively as strong dual proton donors. The potential of 1·HX was shown in the enantioselectiveDiels–Alder reactions of 1-amino dienes with various dienophiles
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
A highly enantio‐ and diastereoselective formal (4+3) cycloaddition of 1,3‐diene‐1‐carbamates with 3‐indolylmethanols in the presence of a chiral phosphoric acid catalyst is reported. The approach described herein provides efficient access to 6‐aminotetrahydrocyclohepta[b]indoles in good yields with mostly complete diastereoselectivity and excellent levels of enantioselectivity (>98:2 dr and up to