Corannulene methylated

In spite of this substantial curvature, corannulene undergoes rapid bowl-to-bowl inversion in solution as demonstrated by the dynamic NMR behavior of its dimethyl carbinol derivative a single signal for the methyl groups appears at ambient temperature while the diastereotopic methyls become observable separately below -64 °C. A barrier to inversion was determined to be AG = 10.2 kcal/mol. In a similar fashion, a barrier of 11.4 kcal/mol was determined for isdpropylcoran-nulene. ... 

Preparation of 2,3-disubstituted corannulene derivatives requires an alternative synthesis (Scheme 9) [57]. 2,3-DiphenyIcorannulene (32) was generated by the Ni-catalyzed Kumada coupling of 2,3-dichlorocorannulene (19) with phenyl-magnesium bromide. Similarly, the Ni-catalyzed methylation of 19 with trimethyl-aluminum yielded 2,3-dimethylcorannulene (33), from which the bis-(bromomethyl) derivative 34 was obtained by benzyUc bromination with M-bromosuccinimide. Moreover, heating 19 in diethylene glycol monomethyl... 

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