Synthesis, Chiral Resolution, and Absolute Configuration of C2-Symmetric, Chiral 9,9′-Spirobifluorenes

• Published in: European journal of organic chemistry Vol. 2014; no. 29; pp. 6513 - 6518
• Main Authors: Stobe, Caroline, Seto, Ryota, Schneider, Andreas, Lützen, Arne
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.10.2014; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: Analytical methods; Chiral resolution; Chromatography; Configuration determination; Liquid chromatography; Spiro compounds
• ISSN: 1434-193X; 1099-0690
• DOI: 10.1002/ejoc.201402738

Racemic 2,2′‐, 2,2′,7,7′‐, and 2,2′,3,3′‐substituted 9,9′‐spirobifluorenes were synthesised and successfully resolved by HPLC on a Chiralpak IA stationary phase on both analytical and semipreparative scales. Their absolute configurations were determined by comparison of their specific optical rotations with literature data or by comparison of retention times with independently prepared enantiopure material. These compounds are versatile C2‐symmetric building blocks for the formation of more sophisticated cleft‐like, chiral molecular architectures. Dissymmetric difunctionalised 9,9′‐spirobifluorene derivatives were prepared and resolved by HPLC on a chiral stationary phase on a semipreparative scale. The absolute configurations of the resolved enantiomers were assigned by comparison of specific optical rotations with literature data or retention times of independently prepared enantiomerically pure material.