New Efficient Procedures for Direct Introduction of the Agrochemically Important β-Methoxypropenoate Unit into Substituted Aromatic Derivatives

Abstract

Two simple and efficient procedures for the synthesis of methyl (E)-2-aryl-3-methoxypropenoates 1 were developed. The first procedure involves a Pd-catalyzed cross-coupling reaction between arylzinc chlorides and methyl (Z)-2-iodo-3-methoxypropenoate 4. The second procedure consists in a Pd-catalyzed cross-coupling reaction between arylboronic acid and methyl (Z)-2-bromo-3-methoxypropenoate 6. This electrophile has been prepared by Pd-catalyzed reaction of methyl (Z)-2,3-dibromopropenoate 7 with Bu₃SnOMe. Other unprecedented regioselective carbon-oxygen bond and carbon-sulfur bond forming reactions occurred when 7 or its stereoisomer was reacted with alkoxy- and arylthio- or alkylthio-tributylstannanes, respectively, in the presence of Pd(PPh₃)₄.