Topological Structural Chemistry of Fused Bicycloalkanes Allowing Homeomorphic Conversions

Abstract

Fused bicycloalkanes have several structures with different orientation of the substituents, such as out,out‐, in,in, and in,out‐structures. Some bicycloalkanes can undergo homeomorphic conversion between certain structures, for instance an out,out‐structure convert to an in,in‐structure. This homeomorphism can be achieved by one chain passing through the macroring. In this report, topological structural chemistry of fused bicycloalkanes and their analogues allowing homeomorphic conversions were reviewed. Although the concept of homeomorphism in fused bicycloalkanes was proposed 50 years ago, comprehensive researches on their structural chemistry are still ongoing. These understandings are highly relevant to the fundamentals of many fields of chemistry, including structural chemistry, theoretical chemistry, natural products chemistry, and materials science.