A general and efficient Pd-catalyzed rapid 2-fluoroethoxylation of bromo-chalcones

• Unprecedented Pd-catalyzed rapid 2-fluroethoxylation of bromo-chalcones has been demonstrated.
• A breakthrough in the Pd-catalyzed CO cross-coupling reactions has been achieved.
• We break the concept of alcohols and fluoroalcohols are known to be weak nucleophiles.
• 2-Fluoroethanol coupled with bromo-chalcone in a little while.
• This procedure can be used for 18F labeling of bromo-chalcones with little modifications.

An efficient unprecedented Pd-catalyzed rapid 2-fluoroethoxylation of bromo-chalcones has been unveiled. The oxygen nucleophiles (fluoroalcohols) experience the rapid CO bond forming reaction for the first time, albeit the alcohols are known to be a weak nucleophile and have greater competing β–hydride elimination in the transition-metal-catalyzed (especially Pd and Cu) CO cross-coupling reaction. The higher fluoroalcohols have also been effectively coupled with bromo-chalcones with relatively lower rate.

An efficient and rapid Pd-catalyzed 2-fluoroethoxylation of bromo-chalcones has been developed for the first time. Unprecedentedly, Pd/tBuXPhos catalyst system efficiently facilitates the rapid CO bond formation, even with weak nucleophilic fluoroalcohols, generally 5–120 min. This catalyst system could also effectively couple the higher fluoroalcohols with bromo-chalcones.Figure optionsDownload as PowerPoint slide