Conformation Design of Open-Chain Compounds.

At the brink of the 21st century, chemistry is increasingly concerned with the function that molecules fulfil as drugs, receptors, or-as ensemble of molecules-as materials. The capability of compounds to fulfil such functions cannot sufficiently be described by using only the terms composition and configuration. A decisive role is played in addition by the conformation of the molecules, which serves as the link between molecular composition and molecular function. Expressions such as "active conformation" or "competent conformation" allude to this aspect. Chemists have to develop an understanding how a flexible molecule adopts the conformation (a distinct shape) which is optimal for the function in question and how this process can be controlled. On the outset of such considerations, we may ask how nature succeeded in the process of evolution to endow flexible molecules with a preference to adopt the conformation which is optimal for the function it has to serve. In this review, I report on how we have reached a crude level of understanding of conformation design in nature with reference to the class of polyketide natural products, how we developed these insights into a conformation design of open-chain compounds, and which applications are already in sight.