Regioselectivity in the Stille Coupling Reactions of 3,5-Dibromo-2-pyrone
作者:Won-Suk Kim、Hyung-Jin Kim、Cheon-Gyu Cho
DOI:10.1021/ja037043a
日期:2003.11.1
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
Regiocontrolled Suzuki-Miyaura Couplings of 3,5-Dibromo-2-pyrone
作者:Cheon-Gyu Cho、Ki-Moon Ryu、Arun Kumar Gupta、Jin Wook Han、Chang Ho Oh
DOI:10.1055/s-2004-831311
日期:——
In a similar way to its Stille coupling reactions, 3,5-dibromo-2-pyrone undergoes the Suzuki-Miyaura coupling reactions at either the C3- or the C5-position with high regioselectivity depending on the reaction conditions.
Stille couplings of 3-(trimethylstannyl)-5-bromo-2-pyrone for the syntheses of 3-aryl-5-bromo-2-pyrones and their ambident dienyl characters
作者:Jin-Hee Lee、Won-Suk Kim、Young Yiol Lee、Cheon-Gyu Cho
DOI:10.1016/s0040-4039(02)01182-6
日期:2002.8
3-(Trimethylstannyl)-5-bromo-2-pyrone underwent facile Stille Coupling reactions with aryl halides to produce various 3-substituted 5-bromo-2-pyrones. The resulting 3-aryl-2-pyrone derivatives underwent both normal and inverse electron demand Diels Alder cycloadditions depending on the type of the dienophiles being reacted. (C) 2002 Elsevier Science Ltd. All rights reserved.