The Chemistry of alpha,beta-Ditosyloxy Ketones: Hypervalent Iodine (III) Mediated Synthesis of Alkynes from alpha, beta-Unsaturated Carbonyl Compounds Containing Pyrazole Moiety

作者：Ranjan Pooja; Arora Loveena; Prakash Richa; Aneja Deepak K; Prakash Om

来源：Letters in Organic Chemistry, 2017, 14(4): 236-242.

DOI：10.2174/1570178614666170321121411

• Alkynes
• alpha,beta-chalcone ditosylates
• alpha,beta-chalcone dibromides
• desoxybenzoin
• [hydroxy(tosyloxy)iodo]benzene

Background: The present study is an effort to extend the utility of the alpha,beta-ditosyloxy chalcone derivatives in establishing the reaction patterns of these compounds which at once was thought that they might behave similar to alpha,beta-dibromo ketones but the results obtained were quite different and interesting in nature.
Methods: In the present methodology, the alpha,beta-chalcone ditosylates containing pyrazoles were prepared from corresponding chalcone derivatives on treatment with [hydroxyl(tosyloxy) iodo] benzene in dichloromethane at room temperature and that were further allowed to react with potassium hydroxide in methanol.
Results: A new series of acetylenic ketones were obtained in the present case in excellent yield. The analytical data of the compounds fully satisfy the structures of the compounds.
Conclusions: In the present case, the alpha,beta-chalcone ditosylates lead to the elimination of ditosyloxy groups and the products isolated are acetylenic ketones which are stable under the reaction conditions. Hence, it offers a facile and convenient route for the synthesis of acetylenic ketones which are difficult to synthesize otherwise.

• 出版日期2017