The reaction between hydrazonoyl chlorides and monosubstituted allenes in the presence of catalytic amounts of copper(I) chloride gives 1,3,5-substituted pyrazoles under mild conditions and very short reaction times. This site- and regioselective process involves first the complexation of copper(I) on the external double bond of the allene moiety, followed by nucleophilic attack on the central carbon atom of the so-formed copper(I)-complexed allene by the terminal nitrogen of the hydrazonoyl chloride. Subsequent ring closure to the target pyrazole ring is possible in the presence of electron-attracting groups on the allene moiety. A catalytic cycle has been proposed on the basis of the experimental results.
When Hydrazonoyl Chlorides Meet Allenes: a Site- and Regio-Selective Copper(I)-Catalysed Approach to 5-Substituted Pyrazoles / G. Molteni, S. Baroni, M. Manenti, A. Silvani. - In: HETEROCYCLES. - ISSN 0385-5414. - 102:10(2021 Oct), pp. 1995-2006. [10.3987/COM-21-14506]
Titolo: | When Hydrazonoyl Chlorides Meet Allenes: a Site- and Regio-Selective Copper(I)-Catalysed Approach to 5-Substituted Pyrazoles | |
Autori: | MANENTI, MARCO (Penultimo) SILVANI, ALESSANDRA (Ultimo) | |
Settore Scientifico Disciplinare: | Settore CHIM/06 - Chimica Organica | |
Data di pubblicazione: | ott-2021 | |
Rivista: | ||
Tipologia: | Article (author) | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.3987/COM-21-14506 | |
Appare nelle tipologie: | 01 - Articolo su periodico |
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