508234-62-6Relevant academic research and scientific papers
Regioselectivity in the Stille Coupling Reactions of 3,5-Dibromo-2-pyrone
Kim, Won-Suk,Kim, Hyung-Jin,Cho, Cheon-Gyu
, p. 14288 - 14289 (2003)
The Stille couplings of 3,5-dibromo-2-pyrone normally take place regioselectively at C3, lower in electron density than C5, thus oxidative addition proceeds faster . When the reactions are carried out with Cu(I) in DMF or other polar aprotic solvent, however, the couplings occur predominantly at C5. The observed regiochemical reversal is attributed to the preferred formation of 5-pallado-2-pyrone intermediate which, in addition, turned out to be more reactive than 3-pallado-2-pyrone intermediate. Copyright
Regioselective Stille coupling reactions of 3,5-dibromo-2-pyrone with various aryl and vinyl stannanes
Kim, Won-Suk,Kim, Hyung-Jin,Cho, Cheon-Gyu
, p. 9015 - 9017 (2007/10/03)
3,5-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.
