1,2-Diaza-1,3-dienes readily react as Michael acceptors with thiocyanic acid generated in situ from potassium thiocyanate. The acidic medium of the reaction promotes the intramolecular ring closure of the α-thiocyanato hydrazones allowing access to novel 2-imino-4-thiazolines functionalized at positions 3, 4, and 5 in a one-pot, high-yielding process.
Divergent Approach to Thiazolylidene Derivatives: A Perspective on the Synthesis of a Heterocyclic Skeleton from β-Amidothioamides Reactivity
作者:Stefania Santeusanio、Roberta Majer、Francesca Romana Perrulli、Lucia De Crescentini、Gianfranco Favi、Gianluca Giorgi、Fabio Mantellini
DOI:10.1021/acs.joc.7b02135
日期:2017.9.15
Herein we report a domino protocol able to reach regioselectively thiazolylidene systems by combining the reactive peculiarities of both β-amidothioamides (ATAs) and 1,2-diaza-1,3-dienes (DDs). Depending on the reaction conditions and/or the nature of the residue at C4 of the heterodiene system, ATAs can act as hetero-mononucleophiles or hetero-dinucleophiles in the diversified thiazolylidene ring
Conjugated azoalkenes. Part VI. α-Olefinated carbonyl derivatives by treatment of azoalkenes with carbomethoxymethylene triphenylphosphorane
作者:Orazio A. Attanasi、Paolino Filippone、Stefania Santeusanio
DOI:10.1016/s0040-4039(00)82192-9
日期:1988.1
α-Olefinated carbonyl derivatives have been obtained in good yield under very mild conditions by Wittig-type reaction of some conjugated azoalkenes with carbomethoxymethylene triphenylphosphorane. The reaction mechanism seems to implicate zwitterionic rather than cycloadduct intermediate, as usual for the Wittig reaction.
Zn(II)-Catalyzed Addition of Aromatic/Heteroaromatic C(sp<sup>2</sup>)–H to Azoalkenes: A Polarity-Reversed Arylation of Carbonyl Compounds
作者:Cecilia Ciccolini、Lucia De Crescentini、Fabio Mantellini、Stefania Santeusanio、Gianfranco Favi
DOI:10.1021/acs.orglett.9b01628
日期:2019.6.7
An umpolung α-(hetero)arylation strategy that involves the Michael-type reaction between electron-rich (hetero)aromatic substrates and azoalkenes is developed. The reaction proceeds under very mild conditions at room temperature and in the presence of inexpensive, nontoxic ZnCl2 catalyst to provide access to otherwise inaccessible hydrazone structures. Subsequent hydrolysis of these latter to ketones
Substrate-controlled reactions have been developed for the synthesis of spirocyclopropylpyrazolones and bicyclic 4,5-dihydropyrazoles from 1,2-diaza-1,3-dienes and sulfur ylides. These protocols were carried out under mild reaction conditions without any additives in generally moderate to good yields. Plausible mechanisms for the transformations were proposed.