Optisch aktive, aromatische Spirane, 9. Mitt.: Überprüfung eines Näherungsansatzes für Chiralitätsfunktionen bei 5,5′,6′-trisubstituierten 2,2′-Spirobiindanen

摘要

In order to test the semiempirical value of chirality functions in their mathematically most simple form 23 new optically active 5,5′-disubstituted 2,2′-spirobiindanes1of known chirality and enantiomeric purity were prepared. Thus a set of about hundred compounds is now available with altogether sixteen types of ligands (i.e. substituents including hydrogen); the experimental molar rotation of fifteen compounds is used to determine the value of a ligandspecific parameter occuring in the used chirality polynomial. According to theory this polynomial is an approximation for the total rotation of derivatives with ligands of three different types and it approximates an experimentally separable part of the rotation as far as compounds with four different ligands are concer