作者:Rudolf J. Vermeij、David O. Miller、Louise N. Dawe、Ivan Aprahamian、Tuvia Sheradsky、Mordecai Rabinovitz、Graham J. Bodwell
DOI:10.1071/ch10356
日期:——
have been successful. The syntheses of two [2.2]cyclophanes with very large Δd values, [2]paracyclo[2](2,7)pyrenophane (17) (Δd = 4.25 Å) and [2]metacyclo[2](2,7)pyrenophane (18) (Δd = 5.04 Å) are presented here. The syntheses hinge on a valence isomerization/dehydrogenation reaction. The crystallographically determined bend angle, θ, for 18 is 96.1°. Cyclophane 18 undergoes a degenerate conformational
上[2.2]环芳文献的检查揭示(如由参数Δ测量的两个“半环芳”的相对大小之间的关系松散d)和占主导地位的一般合成方法的限制。直接耦合方法往往仅对Δd值低于1.0Å的系统成功,而基于环收缩的方法通常对于Δd值高达2.0Å的系统是可行的。对于极少数已知的Δd值大于2.0Å的系统,基于芳构化的方法是唯一成功的方法。2 [2.2]环芳的具有非常大的Δ的合成d值,[2] paracyclo [2](2,7)pyrenophane(17)(Δ d = 4.25)和[2] metacyclo [2](2,7)pyrenophane(18)(Δ d = 5.04埃)在此提出。合成取决于化合价化合/脱氢反应。晶体学确定的18的弯曲角θ为96.1°。环环烷18经历简并的构象翻转,通过DNMR测定其能垒为18.9 kcal mol –1。