The concept of "regioexhaustive substitution" has been successfully applied to 2-fluoro-, 2,3-difluoro-, and 2,5-difluoropyridine. All vacant positions were amenable to regioselective metalation and subsequent carboxylation by employing either chlorine as a neighboring site activating protective group or trimethylsilyl as a neighboring site screening protective group. In this way, approx. half a dozen fluorinated pyridinecarboxylic acids were derived from each starting material. [on SciFinder (R)]
Title
Selective Functionalization of 2-Fluoropyridine, 2,3-Difluoropyridine, and 2,5-Difluoropyridine at Each Vacant Position
Published in
Journal of Organic Chemistry
Volume
70
Issue
8
Pages
3039-3045
Date
2005
Note
CAN 142:447088 27-16 Heterocyclic Compounds (One Hetero Atom) Institute of Chemical Sciences and Engineering (ISIC-BCh),Ecole Polytechnique Federale,Lausanne,Switz. Journal 0022-3263 written in English. 372-48-5 (2-Fluoropyridine); 994-30-9 (Chlorotriethylsilane); 1513-66-2 (2,3-Difluoropyridine); 84476-99-3 (2,5-Difluoropyridine) Role: RCT (Reactant), RACT (Reactant or reagent) (selective functionalization of 2-fluoropyridine, 2,3-difluoropyridine, and 2,5-difluoropyridine at each vacant position via regioselective metalation and subsequent carboxylation); 1480-64-4P (3-Chloro-2-fluoropyridine); 741683-19-2P; 851178-99-9P; 851179-03-8P; 851386-27-1P; 851386-28-2P; 851386-29-3P; 851386-30-6P; 851386-32-8P; 851386-34-0P; 851386-35-1P; 851386-36-2P; 851386-37-3P; 851386-40-8P; 851386-41-9P; 851386-42-0P; 851386-44-2P; 851386-46-4P; 851386-47-5P; 851386-48-6P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (selective functionalization of 2-fluoropyridine, 2,3-difluoropyridine, and 2,5-difluoropyridine at each vacant position via regioselective metalation and subsequent carboxylation); 393-55-5P (2-Fluoropyridine-3-carboxylic acid); 402-65-3P (2-Fluoropyridine-4-carboxylic acid); 402-69-7P (6-Fluoropyridine-2-carboxylic acid); 403-45-2P (6-Fluoropyridine-3-carboxylic acid); 851386-31-7P; 851386-33-9P; 851386-38-4P; 851386-39-5P; 851386-43-1P; 851386-45-3P Role: SPN (Synthetic preparation), PREP (Preparation) (selective functionalization of 2-fluoropyridine, 2,3-difluoropyridine, and 2,5-difluoropyridine at each vacant position via regioselective metalation and subsequent carboxylation)
Record creation date
2006-03-03
