Aluminum Triflate Catalyzed Tandem Reactions of d-Galactal: Toward Chiral Benzopyrans, Chromenes, and Chromans

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• 作者：Sandile B. Simelane ; Henok H. Kinfe ; Alfred Muller ; D. Bradley G. Williams
• 刊名：Organic Letters
• 出版年：2014
• 出版时间：September 5, 2014
• 年：2014
• 卷：16
• 期：17
• 页码：4543-4545
• 全文大小：280K
• ISSN：1523-7052

文摘

3,4,6-Tri-O-acetyl-d-galactal is selectively converted into 1-O-aryl-2-deoxy derivatives or chiral bridged benzopyrans under Al(OTf)₃ catalysis, depending on reaction conditions. The benzopyrans react with Al(OTf)₃/acetic anhydride in ring-opening reactions in the absence or presence of acetic acid to selectively produce chiral chromenes or chromans, respectively, in high yields.