Brnsted Acid Catalyzed Formal Insertion of Isocyanides into a C-O Bond of Acetals

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• 作者：Mamoru Tobisu ; Aki Kitajima ; Sachiko Yoshioka ; Isao Hyodo ; Masayuki Oshita ; Naoto Chatani
• 刊名：Journal of the American Chemical Society
• 出版年：2007
• 出版时间：September 19, 2007
• 年：2007
• 卷：129
• 期：37
• 页码：11431 - 11437
• 全文大小：161K
• 年卷期：v.129,no.37(September 19, 2007)
• ISSN：1520-5126

文摘

The Brnsted acid catalyzed formal insertion of an isocyanide into a C-O bond of an acetal isdescribed. A diverse array of acyclic and cyclic acetals can be applied to the catalytic insertion to form-alkoxy imidates. Functional groups, such as nitro, cyano, halogen, ester, and alkoxy groups, are tolerantto the reaction conditions employed. The course of the reaction is highly dependent on the structure of theisocyanide. The use of an electron-deficient aryl isocyanide, such as 2c and 2d, is required to selectivelyobtain the monoinsertion product. When aryl isocyanides containing alkyl substituents, such as 2a and 2b,are employed, two molecules of the isocyanide are incorporated, and the double-insertion product isobtained. The reaction of tert-octyl isocyanide also induces a double incorporation, but the subsequentacid-mediated fragmentation leads to the 2-alkoxy imidoyl cyanide. The monoinsertion products, -alkoxyimidates, can readily be hydrolyzed to -alkoxy esters, realizing the formal carbonylation of an acetal.