The tropyliumcation has been treated with the hindered bases triphenylmethyl sodium, 2,6-dimethoxy-phenyl lithium, and 2,4,6-tri-t-butylphenyl lithium to give substituted cycloheptatrienes. Where possible its reaction with tertiary amines follows Reaction Scheme 1 to give immonium salts which can be hydrolyzed to tropylated aldehydes and ketones. Its reaction with trimethylamine gives the quaternary