Studies on the Himbert Intramolecular Arene/Allene Diels鈥揂lder Cycloaddition. Mechanistic Studies and Expansion of Scope to All-Carbon Tethers

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• 作者：Yvonne Schmidt ; Jonathan K. Lam ; Hung V. Pham ; K. N. Houk ; Christopher D. Vanderwal
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：May 15, 2013
• 年：2013
• 卷：135
• 期：19
• 页码：7339-7348
• 全文大小：766K
• 年卷期：v.135,no.19(May 15, 2013)
• ISSN：1520-5126

文摘

The unusual intramolecular arene/allene cycloaddition described 30 years ago by Himbert permits rapid access to strained polycyclic compounds that offer great potential for the synthesis of complex scaffolds. To more fully understand the mechanism of this cycloaddition reaction, and to guide efforts to extend its scope to new substrates, quantum mechanical computational methods were employed in concert with laboratory experiments. These studies indicated that the cycloadditions likely proceed via concerted processes; a stepwise biradical mechanism was shown to be higher in energy in the cases studied. The original Himbert cycloaddition chemistry is also extended from heterocyclic to carbocyclic systems, with computational guidance used to predict thermodynamically favorable cases. Complex polycyclic scaffolds result from the combination of the cycloaddition and subsequent ring-rearrangement metathesis reactions.