Regioselective Stille coupling reactions of 3,5-dibromo-2-pyrone with various aryl and vinyl stannanes

✍ Scribed by Won-Suk Kim; Hyung-Jin Kim; Cheon-Gyu Cho

• Book ID: 104252453
• Publisher: Elsevier Science
• Year: 2002
• Tongue: French
• Weight: 259 KB
• Volume: 43
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(02)02305-5

✦ Synopsis

Dibromo-2-pyrone underwent facile regioselective Stille coupling reactions with aryl, heteroaryl and vinyl stannanes to produce various 3-substituted, 5-bromo-2-pyrones. Addition of a catalytic amount of CuI greatly increased the selectivity and chemical yield of the desired 3-aryl-5-bromo-2-pyrone. Second Stille coupling reactions on the resulting 3-aryl-2-pyrones gave rise to a series of potentially useful 2-pyrones with two different functionalities at C3 and C5 position in good to excellent isolated yields. 2-Pyrones with pyridyl groups at C3 position can undergo Lewis acid catalyzed Diels-Alder cycloaddition reactions with benzyl vinyl ether.