Lanthanum Tricyanide-Catalyzed Acyl Silane−Ketone Benzoin Additions and Kinetic Resolution of Resultant α-Silyloxyketones

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• 作者：James C. Tarr ; Jeffrey S. Johnson
• 刊名：Journal of Organic Chemistry
• 出版年：2010
• 出版时间：May 21, 2010
• 年：2010
• 卷：75
• 期：10
• 页码：3317-3325
• 全文大小：1025K
• 年卷期：v.75,no.10(May 21, 2010)
• ISSN：1520-6904

文摘

We report the full account of our efforts on the lanthanum tricyanide-catalyzed acyl silane−ketone benzoin reaction. The reaction exhibits a wide scope in both acyl silane (aryl, alkyl) and ketone (aryl-alkyl, alkyl-alkyl, aryl-aryl, alkenyl-alkyl, alkynyl-alkyl) coupling partners. The diastereoselectivity of the reaction has been examined in both cyclic and acyclic systems. Cyclohexanones give products arising from equatorial attack by the acyl silane. The diastereoselectivity of acyl silane addition to acyclic α-hydroxy ketones can be controlled by varying the protecting group to obtain either Felkin−Ahn or chelation control. The resultant α-silyloxyketone products can be resolved with selectivity factors from 10 to 15 by subjecting racemic ketone benzoin products to CBS reduction.