A general route for 13C-labeled fluorenols and phenanthrenols via palladium-catalyzed cross-coupling and one-carbon homologation

Abstract

A series of (13)C-labeled polyaromatic hydrocarbons (PAHs), fluorenols and phenanthrenols were synthesized from commercially available (13)C-labeled starting material giving rise to M + 6 isotopomers. This was accomplished using key palladium-catalyzed cross-coupling and one-carbon homologation strategies. The conditions for these reactions were optimized, and the new chemical routes are efficient in the number of chemical steps, can be scaled to afford gram quantities and occur in good yields based on the (13)C label. These labeled compounds as precursors for more complex PAHs and are useful as internal standards in mass spectrometry and NMR spectroscopy studies for monitoring environmental contamination and biological exposure to PAHs and their metabolites.

Keywords: mass spectral standards; one-carbon homologation; palladium-catalyzed cross-coupling; polyaromatic hydrocarbons; uniformly 13C-labeled benzene and Friedel-Crafts reactions.