Dimerization of Indanedioneketene to Spiro-oxetanone: A Theoretical Study

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• 作者：Evangelos G. Bakalbassis ; Elizabeth Malamidou-Xenikaki ; Spyros Spyroudis ; Sotiris S. Xantheas
• 刊名：Journal of Organic Chemistry
• 出版年：2010
• 出版时间：August 20, 2010
• 年：2010
• 卷：75
• 期：16
• 页码：5499-5504
• 全文大小：849K
• 年卷期：v.75,no.16(August 20, 2010)
• ISSN：1520-6904

文摘

Indanedioneketene, a compound resulting from the thermal degradation of the phenyliodonium ylide of lawsone, dimerizes quantitatively to a spiro-oxetanone derivative, a key compound for further transformations. A theoretical electronic structure study of this unusual for α-oxoketenes [2 + 2] cyclization reaction both in the gas phase (DFT, MP2) and in dichloromethane solution (DFT), provides support for (a) a single-step, transition-state (involving a four-membered cyclic ring) charge-controlled, concerted mechanism and (b) a [4 + 2] cyclization reaction, not observed but studied theoretically in this study. A parallel study of an open-chain α,α′-dioxoketene dimerization explains the difference in the stability and reactivity observed experimentally between the cyclic and open-chain products.