Abstract
| - Addition of organolithium reagents to corannulene (1) produces 1-R-1,2-dihydrocorannulenes (2),which can be easily converted to 1-R-corannulenes (3). Molecular mechanics (MM) calculationspredict a slight pseudoequatorial preference for the small substituents in both exo and endoarrangements of 2, whereas bulky substituents are expected to favor strongly the exo-pseudoaxiallocation. X-ray diffraction studies show the exo-pseudoaxial conformation in the solid state for bothi-Pr and t-Bu-2. In solution, a gradual increase in the contribution of pseudoequatorial conformationswith decreasing size of the substituent is demonstrated by analysis of the 3J H−H coupling constantswithin the reduced ring.
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