In:
Chemistry – A European Journal, Wiley, Vol. 24, No. 26 ( 2018-05-07), p. 6705-6711
Abstract:
An unprecedented divergent outcome transformation of alkyne tethered N ‐sulfonyl hydrazones is reported, which provides a direct and effective access to 4‐methyl 2 H ‐chromene derivatives and spiro‐4 H ‐pyrazoles in the presence of copper catalyst or under thermal conditions, respectively. The notable features of this process include readily available starting materials, an inexpensive copper catalyst, mild reaction conditions, broad substrate scope, diverse transformations and potential applications of these generated products. Mechanistic studies indicate that the 3 H ‐pyrazole, which is generated via direct [3+2] cycloaddition, is the communal key intermediate of these two divergent transformations. To the best of our knowledge, this is the only example of sulfonation reaction that goes through a cascade process involving 3 H ‐pyrazole, which was isolated and confirmed by single crystal X‐ray diffraction analysis for the first time.
Type of Medium:
Online Resource
ISSN:
0947-6539
,
1521-3765
DOI:
10.1002/chem.201704759
Language:
English
Publisher:
Wiley
Publication Date:
2018
detail.hit.zdb_id:
1478547-X
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