N. Hamdi, P. Dixneuf, A. Khemiss
Aug 1, 2005
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0
Influential Citations
5
Citations
Journal
European Journal of Organic Chemistry
Abstract
The 1,3-dipolar cycloaddition of 2-diazopropane (1) to propargylic alcohols is regioselective and leads to 3H-pyrazoles 3 in good yield. The surprising formation of the tetrasubstituted 3H-pyrazole 4c from HC≡CCH2OH and 1 can be explained by formation of an initial 1,3-dipolar cycloadduct intermediate followed by a second cycloaddition of 1 to the C=C bond and loss of dinitrogen. Photolysis of the antibacterial 3H-pyrazoles 3 and 4 selectively gives α- and β-dimethylcyclopropenyl alcohols 5 and 6, respectively. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)