Reaction of diphenylcyclopropenone with N-acylamidine derivatives. Synthetic and mechanistic implications

Abstract

A reatividade de ciclopropenonas frente a derivados de N-acilamidinas foi investigada. Difenilciclopropenona reagiu com N-benzoilacetamidina e com N-(metoxicarbonil)benzamidina formando 1,2-diidro-3H-pirrol-3-onas em rendimentos moderados, porém alquilfenilciclopropenonas não reagiram com os mesmos nucleófilos investigados. A teoria dos orbitais moleculares de fronteira foi empregada para racionalizar a formação dos produtos.In this work, the reactivity of cyclopropenones toward N-acylamidine derivatives was investigated. Diphenylcyclopropenone reacted with N-benzoylacetamidine and N-(methoxycarbonyl)benzamidine affording 1,2-dihydro-3H-pyrrol-3-ones in moderate yields. However, alkylphenylcyclopropenone did not react. The formation of the compounds is examined mechanistically within frontier molecular orbital considerations.

On the Reactivity of α-(Triphenylphosphoranylidene)-benzylphenylketene with Nitrogen Compounds: Synthetic and Mechanistic Implications

“…As expected, this solid is stable only under anhydrous conditions, but alternatively it can be generated in situ. 2 Thus, equimolar amounts of triphenylphosphine and diphenylcyclopropenone (1) were reacted under inert atmosphere and then the nucleophile was introduced (see Experimental). Among the broad spectrum of nitrogen nucleophiles available, we selected ones whose reactivity toward diphenylcyclopropenone was known.…”

“…Among the broad spectrum of nitrogen nucleophiles available, we selected ones whose reactivity toward diphenylcyclopropenone was known. Thus, we began our study with 2-amino-4-methylpyridine 3, 9 pyridinium N-imine 4 10 and N-benzoylacetamidine 5 1 (examples of reactivity towards 1 are shown in Scheme 1).…”

“…While the reactivity of diphenylcyclopropenone (1) with nucleophiles has been well documented, 1 studies of the behavior of its derivative α-(Triphenylphosphoranylidene)-benzylphenylketene (2, α-TPBPK) with such reagents are scarce. 2 Otherwise, phosphorus ylides have been intensively used in organic synthesis, mainly in olefination reactions.…”

Structural and reactivity analyses of 2-benzylamino-1,4-naphthoquinone by X-ray characterization, electrochemical measurements, and dft single-molecule calculations

“…2,14,15 Despite 1 has been described many years ago, new developments in its preparations have been reported, 16,17 and considering its synthetic and biological applications, no structural study of such compound seems to be described in the literature. In this way, in our ongoing investigation on the chemistry of enaminones, [18][19][20][21][22] we describe herein our results concerning the structural and reactivity analyses through X-ray solid state characterization, electrochemical measurements, and employing density functional theory calculations for this substance.…”

Reatividade de ciclopropenonas frente a nucleófilos e sua correlação com potenciais de redução em meio aprótico

“…Estudos desta natureza podem tomar novas proporções em função da possibilidade de se correlacionar medidas eletroquímicas e atividade biológica. 13 Nosso interesse na compreensão da reatividade de ciclopropenonas e sua aplicação na síntese de heterociclos 14,15 nos motivou a investigar o comportamento eletroquímico das ciclopropenonas 1a,b e da isopropilfenilciclopropenona 1c, Figura 1, procurando estabelecer comparação com o comportamento químico descrito na literatura, obtendo dados experimentais que possibilitem sugerir as razões eletrô-nicas para a ordem de reatividade destas substâncias. Adicionalmente, investigamos a reatividade da isopropilfenilciclopropenona frente a alguns nucleófilos cujas reações com as ciclopropenonas 1a,b são conhecidas, para melhor avaliar o efeito do impedimento estérico na reatividade das ciclopropenonas.…”