Remarkable Efficiency of the Aryne Chemistry of (Dehydro)octafluoro[2.2]paracyclophane When Using the Cadogan Method
摘要:
[GRAPHIC]Generation of the aryne, (dehydro)octafluoro[2.2]paracyclophane, from its acetamide derivative utilizing the Cadogan method led to remarkable results with respect to Diels-Alder and ene reactivity. A comparison was made between this new and virtually unused method and our earlier reported results using Cram methodology (reaction of aryl iodide with potassium tert-butoxide). Surprisingly, no ene reactivity was observed with the Cram methodology. This mechanistic conundrum was examined extensively with no unambiguous explanation for the difference in reactivity being found.
4,5-Dehydrooctafluoro[2.2]paracyclophane: facile generation and extraordinary Diels–Alder reactivity
作者:Merle A. Battiste、Jian-Xin Duan、Yi-An Zhai、Ion Ghiviriga、Khalil A. Abboud、Adrian Roitberg、G.Robert Shelton、William R. Dolbier
DOI:10.1016/s0040-4039(02)01554-x
日期:2002.9
Dehydroiodination of 4-iodo-1,1,2,2,9,9,10,10-octafluoro[2.2]paracyclophane by treatment with KO'Bu in the presence of benzene, naphthalene, anthracene, or t-butylbenzene affords each of the corresponding Diels-Alder cycloadducts of the presumed aryne intermediate in high yield. The products were characterized by their NMR spectra, with one of them also being confirmed by X-ray crystallography. The extraordinary selectivity/reactivity of the aryne intermediate is discussed. (C) 2002 Published by Elsevier Science Ltd.