ap-9-(o-tert-butylphenyl)-9-methylthioluorene, the first isolated ap rotamer of a 9-substituted 9-(o-tert-butylphenyl)fluorene

Treatment of sp-9-(o-tert-butylphenyl)-9-fluorenol with HBr and methanethio l provided ap-9-(o-tert-butylphenyl)-9-methylthiofluorene, C24H24S, exclusi vely, the first isolated ap rotamer of a 9-substituted 9-(o-tert-butylpheny l)fluorene. The ap configuration in this series, generally the thermodynami cally less favored, is preferred in the case of the title compound because the even larger interaction between the tert-butyl group and S in the sp co nfiguration is energetically forbidden. The extensive distortion in the tit le compound is obvious from its X-ray structure and the associated geometri c parameters.