Reactions of Alkyl Azides and Ketones as Mediated by Lewis Acids: Schmidt and Mannich Reactions Using Azide Precursors

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• 作者：Pankaj Desai ; Klaas Schildknegt ; Konstantinos A. Agrios ; Craig Mossman ; Gregory L. Milligan ; and Jeffrey Aubé
• 刊名：Journal of the American Chemical Society
• 出版年：2000
• 出版时间：August 2, 2000
• 年：2000
• 卷：122
• 期：30
• 页码：7226 - 7232
• 全文大小：305K
• 年卷期：v.122,no.30(August 2, 2000)
• ISSN：1520-5126

文摘

The Lewis acid-promoted reactions of alkyl azides with ketones can afford several products. Chiefamong these result from a Schmidt-like insertion of the azide into the carbon-carbon bond adjacent to thecarbonyl group. Alternatively, an acid-promoted rearrangement of the azide to an iminium species can occur,mostly with benzylic azides; the iminium species can then be trapped by the enol of the carbonyl compoundin a variation of the Mannich reaction. The scope of each of these reactions, the dependence of the observedproducts upon azide and ketone structure, and the nature of acid promotion are discussed. In broad strokes,cyclohexanones and other cyclic ketones react in the presence of TiCl₄ to afford insertion products, whereasthe Mannich route predominates when benzyl azide and triflic acid are used. The features that lead to eachreaction type and possible mechanistic implications are discussed.