双环[1.1.1]戊烷环系中桥头-桥头相互作用的表现

Manifestations of Bridgehead-Bridgehead Interactions in the Bicyclo[1.1.1]pentane Ring System.

作者信息

Adcock William, Blokhin Andrei V., Elsey Gordon M., Head Nicholas H., Krstic Alexander R., Levin Michael D., Michl Josef, Munton Jamie, Pinkhassik Evgueni, Robert Marc, Savéant Jean-Michel, Shtarev Alexander, Stibor Ivan

机构信息

Department of Chemistry, The Flinders University of South Australia, Adelaide, Australia, 5001, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Department of Chemical Sciences, Deakin University, Geelong, Victoria, Australia 3217, Laboratoire a' Electrochimie Moléculaire de L'Université Denis Diderot (Paris 7), 2 place Jussieu, 75251 Paris Cedex 05, France, and Institute of Chemical Technology, Prague, Czech Republic.

出版信息

J Org Chem. 1999 Apr 16;64(8):2618-2625. doi: 10.1021/jo982124o.

DOI:10.1021/jo982124o

PMID:11674328

Abstract

A series of 3-halo-substituted bicyclo[1.1.1]pentane-1-carboxylic acids 1 (Y = COOH; X = F, Cl, Br, I, and CF(3)) as well as the parent compound 1 (Y = COOH, X = H) have been prepared, and a study of some of their properties have been made. It was found that their reactions with xenon difluoride cover a wide range of reactivities. On one hand, the fluoro acid 1 (Y = COOH, X = F) displayed no apparent reaction at all while, on the other, the bromo acid 1 (Y = COOH, X = Br) and parent compound 1 (Y = COOH, X = H) underwent ready reaction with complete disintegration of the ring system. A possible explanation is advanced based on polar kinetic and thermodynamic effects governing the lifetime of an intermediate acyloxy radical species. The relative ease of oxidation of the carboxylates 1 (Y = COO(-); X = H, F, Cl, Br, I, CF(3), and COOCH(3)), as mirrored by their peak oxidation potential values (E(p)) determined by cyclic voltammetry, also covers a wide range. These data coupled with the dissociation constants (pK(a)) of some of the acids 1 (Y = COOH; X = H, F, Cl, and CF(3)) reflect significantly on the modes of transmission of electronic effects acting through the bicyclo[1.1.1]pentane ring system.

摘要

已制备出一系列3-卤代双环[1.1.1]戊烷-1-羧酸1（Y = COOH；X = F、Cl、Br、I和CF(3)）以及母体化合物1（Y = COOH，X = H），并对它们的一些性质进行了研究。发现它们与二氟化氙的反应具有广泛的反应活性。一方面，氟代酸1（Y = COOH，X = F）根本没有明显反应，而另一方面，溴代酸1（Y = COOH，X = Br）和母体化合物1（Y = COOH，X = H）则很容易发生反应，环系完全分解。基于控制中间体酰氧基自由基寿命的极性动力学和热力学效应，提出了一种可能的解释。通过循环伏安法测定的羧酸盐1（Y = COO(-)；X = H、F、Cl、Br、I、CF(3)和COOCH(3)）的峰值氧化电位值（E(p)）所反映的它们相对容易被氧化的程度也涵盖了很广的范围。这些数据与一些酸1（Y = COOH；X = H、F、Cl和CF(3)）的解离常数（pK(a)）一起，显著反映了通过双环[1.1.1]戊烷环系起作用的电子效应的传递模式。