Experimental and Theoretical DFT Investigations in the [2,3]-Wittig-Type Rearrangement of Propargyl/Allyl-Oxy-Pyrazolones
Lucia De Crescentini,
Gianfranco Favi,
Giacomo Mari,
Gianluca Ciancaleoni,
Marcello Costamagna,
Stefania Santeusanio,
Fabio Mantellini
Affiliations
Lucia De Crescentini
Department of Biomolecular Sciences, Section of Organic Chemistry and Organic Natural Compounds, University of Urbino “Carlo Bo”, Via I Maggetti 24, 61029 Urbino, PU, Italy
Gianfranco Favi
Department of Biomolecular Sciences, Section of Organic Chemistry and Organic Natural Compounds, University of Urbino “Carlo Bo”, Via I Maggetti 24, 61029 Urbino, PU, Italy
Giacomo Mari
Department of Biomolecular Sciences, Section of Organic Chemistry and Organic Natural Compounds, University of Urbino “Carlo Bo”, Via I Maggetti 24, 61029 Urbino, PU, Italy
Gianluca Ciancaleoni
Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, PI, Italy
Marcello Costamagna
Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, PI, Italy
Stefania Santeusanio
Department of Biomolecular Sciences, Section of Organic Chemistry and Organic Natural Compounds, University of Urbino “Carlo Bo”, Via I Maggetti 24, 61029 Urbino, PU, Italy
Fabio Mantellini
Department of Biomolecular Sciences, Section of Organic Chemistry and Organic Natural Compounds, University of Urbino “Carlo Bo”, Via I Maggetti 24, 61029 Urbino, PU, Italy
Here we report the synthesis of interesting 3-alkyl-4-hydroxy-1-aryl-4-(propa-1,2-dienyl)1H-pyrazol-5(4H)-ones and 9-alkyl-7-aryl-1-oxa-7,8-diazaspiro[4.4]nona-3,8-dien-6-ones, starting from 1,2-diaza-1,3-dienes (DDs) and propargyl alcohol. The reaction proceeds through a sequence Michael-type nucleophilic attack/cyclization/[2,3]-Wittig rearrangement. In the same way, the reaction between the aforementioned DDs and allyl alcohol furnished 4-allyl-4-hydroxy-3-alkyl-1-aryl-1H-pyrazol-5(4H)-ones. A DFT study was also carried out, in order to have decisive clarifications about the mechanism.
