Base-catalyzed electrophilic substitution in 2(1H)-quinolinones

Instead of tandem conjugate addition-α-alkylation to C 3 =C 4 double bond of 2(1H)-quinolinones, regioselective C 3 -lithiation and subsequent C 3 - alkylation takes place by reaction with two equivalents of n-butyllithium and several electrophiles