INVESTIGADORES
ASCOLANI Hugo Del Lujan
congresos y reuniones científicas
Título:
Design, Preparation and Chirality Aspects of New Mono-functionalized Helicenes
Autor/es:
M. VAN DER MEIJDEN; T. BALANDINA; S. DE FEYTER; M. LINGENFELDER; N. MURILLO-QUIRÓS; H. ASCOLANI; K. WURST; R. KELLOG
Lugar:
Fort Worth, Texas
Reunión:
Simposio; The 24th International Symposium on Chirality; 2012
Institución organizadora:
The University of Texas at Arlington
Resumen:
In our ongoing investigation of racemizable conglomerates, we became interested in the synthesis and characterization of mono-functionalized helicenes. Many helicenes described thus far in the literature, crystallize as conglomerates. We desired a helicene that contained a functional group that could be readily manipulated. Previously we have synthesised 5-aminohexahelicene. The synthesis of acidic helicene functionalized at the 7-position has now been accomplished as well as 7-methyl derivative. Using two different types of cyclisation reactions we could perform this challenging conversion. This approach may also be used in preparing larger helicenes or helicenes with different functional groups at the 7-position. Intermediate 7-methylhexahelicene can be prepared in 5% overall yield in 9 steps. Oxidation of this methyl compound is difficult but provides the desired acid-functionalized helicene in ca. 18% yield.