Aza‐Michael Addition Reactions of Hydrazones with Activated Alkynes Catalyzed by Nitrogen‐Containing Organic Bases

Synthesis of Pyridazinones through the Copper(I)‐Catalyzed Multicomponent Reaction of Aldehydes, Hydrazines, and Alkynylesters

“…This reaction gave the aza-Michael addition adduct 7 as the sole product (Scheme 3). [10] In addition, when the reaction was performed with phenylhydrazone 5 (Table 1), pyridazinones 4 were obtained in good yields. It seems clear that phenylhydrazone 5 is a possible intermediate in the multicomponent process.…”

“…To investigate the role of the CuI catalyst, we carried out the reaction of aldehyde 1 a , hydrazine 2 a , and alkynylester 3 a under the optimized conditions in the absence of CuI. This reaction gave the aza‐Michael addition adduct 7 as the sole product (Scheme ) 10. In addition, when the reaction was performed with phenylhydrazone 5 (Table 1), pyridazinones 4 were obtained in good yields.…”

“…Intermediate a reacts with CuI to form cuprate b . The Michael addition of b into the carbon–carbon triple bond of the alkynylester10 gives adduct c′ , which after isomerization gives c 12. Michael addition via a trans ‐copper adduct is in accordance with the known ability of organocopper reagents to undergo π complexation with a carbon–carbon triple bond and with a carbonyl group.…”

Organocatalytic transformations of alkynals, alkynones, propriolates, and related electron-deficient alkynes

“…117 The same group has also described the aza-Michael addition reaction of hydrazine with activated alkynes under DABCO catalysis. 118 …”

Unprecedented Double aza‐Michael Addition within a Sapphyrin Core

“…To our knowledge, the formation of adducts of types 11 and 12 are without precedent.T his is true both in terms of the reactivity of the bipyrrole and sapphyrins and the reactions of DMAD.I ti sw ell known that DMAD reacts with ar ange of nucleophiles and dinucleophiles, under very different experimental conditions, to afford am yriad of acyclic or cyclic products. [48,49] However,t ypically, the conjugateaddition of N-nucleophilest oD MAD affords monoa ddition adducts (enamines), [50][51][52][53][54][55] whereas the reaction with N,N'-dinucleophilesg ives cyclic compounds in which one N-atomi sl inked to an acetylenic-derived carbon atom and the second is linked to ac arbonylg roup. [56][57][58] Similarly,t he double aza-Michael addition of N,N'-dinucleophiles to propynoic acid or its esters affords products in which both N-atoms are linked to the terminal carbon atom.…”