Oxabenzonorbornadiene (OBD) is a useful synthetic intermediate, which can be readily activated by transition metal complexes with great face selectivity due to its dual-faced nature and intrinsic angle strain on the alkene. To date, the understanding of transition-metal catalyzed reactions of OBD itself has burgeoned; however, this has not been the case for unsymmetrical OBDs. Throughout the development of these reactions, the nature of C1-substituent has proven to have a profound effect on both the reactivity and selectivity of the outcome of the reaction. Upon substitution, different modes of reactivity arise, contributing to the possibility of multiple stereo-, regio-, and in extreme cases, constitutional isomers, which can provide unique means of constructing a variety of synthetically useful cyclic frameworks. To maximize selectivity, an understanding of bridgehead substituent effects is crucial. To that end, this review outlines hitherto reported examples of bridgehead substituent effects on the chemistry of unsymmetrical C1-substituted OBDs.

Oxabenzonorbornadiene (OBD) 是一种有用的合成中间体，由于其双面性质和对烯烃的固有角应变，它可以很容易地被过渡金属配合物活化，具有很大的面选择性。迄今为止，对 OBD 本身的过渡金属催化反应的理解已经萌芽；然而，对于非对称 OBD，情况并非如此。在这些反应的整个发展过程中，C1 取代基的性质已被证明对反应结果的反应性和选择性都有深远的影响。取代后，会出现不同的反应模式，有助于产生多种立体异构体，区域异构体，在极端情况下，结构异构体可以提供构建各种合成有用的环状框架的独特方法。为了最大限度地提高选择性，了解桥头取代基效应至关重要。为此，本综述概述了迄今为止报道的桥头取代基对不对称 C1 取代 OBD 化学的影响的例子。