A Combined Experimental and Theoretical Study of the Polar [3 + 2] Cycloaddition of Electrophilically Activated Carbonyl Ylides with Aldehydes and Imines

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• 作者：Ghenia Bentabed-Ababsa^† ; ^‡ ; ; Aicha Derdour^‡ ; ; Thierry Roisnel^§ ; ; Jose A. Sez^¶ ; ; Patricia Prez ; Eduardo Chamorro<
• 刊名：Journal of Organic Chemistry
• 出版年：2009
• 出版时间：March 6, 2009
• 年：2009
• 卷：74
• 期：5
• 页码：2120-2133
• 全文大小：539K
• 年卷期：v.74,no.5(March 6, 2009)
• ISSN：1520-6904

文摘

Numerous 2,5-diaryl-1,3-dioxolane-4,4-dicarbonitriles and 2,4-diphenyl-1,3-oxazolidine-5,5-dicarbonitriles have been synthesized by [3 + 2] cycloaddition reactions between carbonyl ylides generated from epoxides and aldehydes or imines. In contrast to the use of aldehydes (3,4,5-trimethoxybenzaldehyde, piperonal, 1-naphthaldehyde, indole-3-carboxaldehyde, furan-2-carboxaldehyde, and thiophene-2-carboxaldehyde), the reactions performed with imines (N-(phenylmethylene)methanamine, N-(1,3-benzodioxol-5-ylmethylene)propylamine, N-(1,3-benzodioxol-5-ylmethylene)butylamine, and N-(1,3-benzodioxol-5-ylmethylene)benzylamine) proceed diastereoselectively. The effect of microwave irradiation on the outcome of the reaction was studied. The mechanism of these [3 + 2] cycloaddition reactions has been theoretically investigated using DFT methods. These cycloadditions, which have one-step mechanisms, consist of the nucleophilic attack of the aldehyde oxygen or imine nitrogen on the carbonyl ylide. For the reaction with aldehydes, a back-donation effect is responsible for the unexpected reverse charge transfer found at the transition structure. The analysis of the reactivity indexes indicates that the large electrophilic character of the carbonyl ylides induces them to act as strong electrophiles in these polar [3 + 2] cycloaddition reactions.