Quinidine-Catalysed Enantioselective Synthesis of 6- and 4-Trifluoromethyl-Substituted Dihydropyrans

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• 作者：Kevin Kasten ; David B. Cordes ; Alexandra M. Z. Slawin and Andrew D. Smith
• 刊名：European Journal of Organic Chemistry
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：2016
• 期：21
• 页码：3619-3624
• 全文大小：1281K
• ISSN：1099-0690

文摘

The cinchona alkaloid-catalysed enantioselective formal [4+2] cycloaddition of ethyl 2,3-butadienoate with a range of 1,1,1-trifluoro- and 4,4,4-trifluorobutenones is investigated for the preparation of stereodefined 6- and 4-trifluoromethyl-substituted dihydropyrans. Quinidine proved to be the optimal catalyst, generating the desired products in up to 98 % m>eem> and 81 % yield. Stereo- and chemoselective derivatization of the dihydropyrans through hydrogenation is explored.