METHODS OF FORMING 4-CHLORO-2-FLUORO-3-SUBSTITUTED-PHENYLBORONIC ACID PINACOL ESTERS AND METHODS OF USING THE SAME
Methods include formation of 4-chloro-2 fluoro-3 substituted-phenylboronic acid pinacol esters. The method comprises contacting a 1-chloro-3-fluoro-2-substituted benzene with an alkyl lithium to form a lithiated 1-chloro-3-fluoro-2-substituted benzene. The lithiated 1-chloro-3-fluoro-2-substituted benzene is contacted with an electrophilic boronic acid derivative to form a 4-chloro-2-fluoro-3-substituted-phenylboronate. The 4-chloro-2-fluoro-3-substituted-phenylboronate is reacted with an aqueous base to form a (4-chloro-2-fluoro-3-substituted phenyl)trihydroxyborate. The (-chloro-2-fluoro-3-substituted phenyl)trihydroxyborate is reacted with an acid to form a 4-chloro-2-fluoro-3-substituted phenylboronic acid. The 4-chloro-2-fluoro-3-substituted phenylboronic acid is reacted with 2,3 dimethyl 2,3 butanediol to form 4-chloro-2-fluoro-3-substituted phenylboronic acid pinacol esters. Methods of using 4-chloro-2-fluoro-3-substituted phenylboronic acid pinacol esters to produce 6 (4-chloro-2-fluoro-3-substituted phenyl) 4 aminopicolinates are also disclosed.