Intramolecular Formal [4 + 2] Cycloaddition of Nitriles with Amides Triggered by TMSOTf/Et3N: Highly Efficient Construction of Pyrrolo[1,2-a]pyrimidin-4(6H)-ones
摘要:
By treatment with TMSOTf/Et3N, N-(2-cyanoarylmethyl)-substituted acrylamides or beta-ketoamides underwent N-addition cascades under mild conditions to afford the corresponding pyrrolo[1,2-a]pyrimidin-4(6H)-ones as the formal [4 + 2] cycloaddition products in high yields.
a tin-free radical cascade cyclizationprocess. Not only do amide-iminyl radicals lead to new tetracyclic heterocycles but these nitrogen-centered radical species also react in aromatic homolytic substitutions. Indeed, the amide-iminyl radical moiety unprecedentedly displaces methyl, methoxy, and fluorine radicalsfrom an aromatic carbon atom. This seminal reaction in the field of radical chemistry