Diastereoselective syntheses of (Z)- and (E)-3-styrylquinolin-4(1H)-ones

Abstract

Two methods for the synthesis of 3-styrylquinolin-4(1H)-ones are presented and discussed. One involves the Heck reaction of a 3-halo-quinolin-4(1H)-one with styrene derivatives, under classical heating conditions and microwave irradiation. The second one has two alternative synthetic routes: one pathway involves the Wittig reaction of quinolin-4(1H)-one-3-carbaldehyde with benzylic ylides and the other one involves the Wittig reaction of 4-chloroquinoline-3-carbaldehyde with the same ylides. The diastereomeric selectivity (Z/E) of 3-styrylquinolin-4(1H)-ones obtained in each synthetic strategic is discussed and compared. The last method was also applied to the synthesis of quinolin-4(1H)-ones bearing 3-substituents with extended π-conjugated systems.