Macro Rings. XXXIV. A Ring Expansion Route to the Higher Paracyclophanes, and Spectra-Structure Correlations of Their Derived Ketones1

DJ Cram, RC Helgeson

Index: Cram,D.J.; Helgeson,R.C. Journal of the American Chemical Society, 1966 , vol. 88, # 15 p. 3515 - 3521

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Citation Number: 53

Abstract

Abstract: Four-step syntheses of [3.3]-,[3.4]-, and [4.4] paracyclophanes from [2.2] paracyclophane are reported in which the critical ring enlarging step involves treatment of either 1, 7-or 1, 8-diket0 [2.2] paracyclophane with appropriate amounts of diazomethane. The yield pattern of homologous ketones suggests thatithe smaller the ring system of the reacting ketone, the faster is the ring expanding step. The best over-all yield (23%) of [3.3] ...