名称:
Chemie freier cyclischer vicinaler Tricarbonyl-Verbindungen (‘1,2,3-Trione') Teil 2. Redox-Reaktionen von 1,2,3-Trionen mit En-1,2-diolen (‘Reduktonen'), 2-Alkoxy-en-1-olen, En-1,2-diaminen und verwandten Spezies Für Teil 1, s. [1].
摘要:
Chemistry of Free Cyclic Vicinal Tricarbonyl Compounds ('1,2,3-Triones'). Part 2. Redox Reactions of 1,2,3-Triones with Ene-1,2-diols ('Reductones'), 2-Alkoxy-en-1-ols, Ene-1,2-diamines, and Related SpeciesMidstanding carbonyl groups of cyclic 1,2,3-triones 4 possess outstanding electrophilic (elcctron-pair accepting) as well as oxidizing (one-electron accepting) properties. Their reactions with selected electron-rich C C bonds as efficient nucleophiles (AN reactions) and as efficient reducing agents (SET (single electron transfer) reactions) are studied. In a few cases, short-lived charge-transfer colors could be observed. Particularly, free didehydro-5,6-0-isopropyliden-L-ascorbic acid (4g), its 0,C-adduct 8g to 5,6-O-isopropylidene-(L)-ascorbic acid (1g), and - via an independent pathway - the ostensible C,C-dimer 10a of mono-dehydrodimedone reductone were prepared. Intermediate radical anions 4- can be considered to be ideal representatives of dicapto-dative radicals. Novel large-scale syntheses of 3,4-dihydroxyfuran-2(5H)-one (1e) and of its vicinal trione 4e are presented.