Intramolecular and intermolecular Schmidt reactions of alkyl azides with aldehydes

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• 作者：Huey-Lih Lee ; Jeffrey Aubé
• 关键词：Schmidt reaction ; Alkyl azide ; Aldehyde
• 刊名：Tetrahedron
• 出版年：2007
• 出版时间：3 September 2007
• 年：2007
• 卷：63
• 期：36
• 页码：9007-9015
• 全文大小：285 K

文摘

Despite recent advances in the use of alkyl azides in ring expansion reactions of ketones, there has been little work done on the corresponding chemistry of aldehydes. In the present study, the Lewis acid-promoted reactions of alkyl azides with aldehydes were studied in both intermolecular and intramolecular contexts. The intramolecular reactions of azidoalkyl aldehydes in which the azide and carbonyl groups were separated by 2–5 carbons were examined. Although the examples having the shortest tether failed (3-azidopropanals), each of the other systems gave good yields of either NH-substituted lactams (resulting from hydride migration in the initially formed azidohydrin adduct) or formamides (alkyl migration). The product formed was dependent on the chain length of the starting azido aldehyde. The intermolecular reactions were less efficient, requiring TiCl₄ promotion for even moderate yields, and in each case gave mixtures of products resulting from hydride and alkyl migration.