C-13 NMR-STUDY OF POLYARYL-C-HETEROARYL-CARBINOL AND POLY-C-HETEROARYL-CARBINOLS AND THEIR CARBONIUM SALTS

The carbon-13 chemical shifts of a series of trisubstituted methanols with phenyl, p-dimethylaminophenyl, 9-fluorenyl, 2-N-methylpyrrolyl, 2-furyl, 2-thienyl, 2-N-methylindolyl, 2-benzofuryl and 2-benzothienyl substituents (26 compounds) are discussed. Those of the sp-3 carbon atoms bearing the OH group, and the ipso carbons carrying the COH group, follow additive models with high accuracy. The corresponding central carbon atom of the carbonium ions, which were stable enough to be studied in chloroform (eight compounds), also follows an additive pattern which allows the prediction of the chemical shifts of derivatives not studied in this work.