Efficient One-Pot Synthesis of 4-Aroyl-2-pyrones: Nucleophilic Addition of Active Methylene Groups to 1,2-Diaroylacetylenes

Quantification of the Nucleophilic Reactivities of Ethyl Arylacetate Anions

“…[2] Furthermore, they can easily be alkylated or added to carbonyl groups, imines, or acetylenes, leading to a wide variety of products of biological and medicinal interest. [1d, [3][4][5] During the last decades, we have constructed a comprehensive nucleophilicity scale, which is based on reactions of π-, n-, and σ-nucleophiles with benzhydrylium ions, structurally related quinone methides, and diethyl benzylidenemalonates. [6][7][8][9][10][11] The second-order rate constants of these reactions have been described by Equation (1), where E is an electrophile-specific parameter, and N and s N are nucleophile-specific parameters.…”

Emission solvatochromic, solid-state and aggregation-induced emissive α-pyrones and emission-tuneable 1H-pyridines by Michael addition–cyclocondensation sequences

“…Tominaga and co-workers synthesized a series of α-pyrone derivatives with emission maxima between 400 and 675 nm in the solid state and between 486 and 542 nm in chloroform [16,24–26], including fluorescence quantum yields as high as 95% in solution and 58% in the solid state [16,24]. While these fluorophores were synthesized by cyclocondensation with ketene dithioacetals and substituted acetophenones other cyano-containing derivatives became accessible by desymmetrizing cyclocondensation of 1,2-diaroylacetylenes with ethyl cyanoacetate [27], similar to related studies with dialkyl malonates [28]. Here, we report on effects of base and temperature on Michael addition–cyclocondensation sequences in the formation of α-pyrones and/or 1 H -pyridines starting from diversely substituted alkynones and cyanoethylacetate.…”