Fluorocarboxyhc acids

Selectivity and reactivity of mixed anhydrides toward primary and secondary aliphatic and aromatic amines has been studied in details [42, 43] (equation 22) Fluorocarboxyhc acids and then denvahves are used as building blocks m condensa non reactions widi dmucleophihc species for the synthesis of fluoroalkyl-subshtuted lieteroaromahc systems [S 9, 40, 44, 45, 46, 47 4S] (equations 20 21, and 23)... 

Synthetic methods employed in this series of compounds As direct chlorination or bromination of a carboxylic acid usually gives the a-substituted acid, such methods are useless for the preparation of the w-substituted acids ad hoc methods therefore had to be found for the preparation of each individual W fluorocarboxyhc acid and its derivatives. 

The reaction has also been used in the preparation of a-fluorocarboxyhc acids with good enantioselectivity, including the conversion of the alkenyl fluoride (2.79) into a-fluorohexanoic acid (2.80). ... 

BINAP/R3SiOTf/2,6-ludidine. Such a reaction allows for the preparation of a-fluorocarboxyhc acid derivatives that have not been as thoroughly explored as activated p-keto esters because of the difficulty in generating metal enolates in situ under catalytic conditions. In this reaction, a substoi-chiometric amount of Et3SiOTf and a stoichiometric amount of the base were required for a high chemical yield. 

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