TY - JOUR
T1 - Palladium-catalyzed carbene migratory insertion using conjugated ene-yne-ketones as carbene precursors
AU - Xia, Ying
AU - Qu, Shuanglin
AU - Xiao, Qing
AU - Wang, Zhi Xiang
AU - Qu, Peiyuan
AU - Chen, Li
AU - Liu, Zhen
AU - Tian, Leiming
AU - Huang, Zhongxing
AU - Zhang, Yan
AU - Wang, Jianbo
PY - 2013/9/11
Y1 - 2013/9/11
N2 - Palladium-catalyzed cross-coupling reactions between benzyl, aryl, or allyl bromides and conjugated ene-yne-ketones lead to the formation of 2-alkenyl-substituted furans. This novel coupling reaction involves oxidative addition, alkyne activation-cyclization, palladium carbene migratory insertion, β-hydride elimination, and catalyst regeneration. Palladium (2-furyl)carbene is proposed as the key intermediate, which is supported by DFT calculations. The palladium carbene character of the key intermediate is validated by three aspects, including bond lengths, Wiberg bond order indices, and molecular orbitals, by comparison to those reported for stable palladium carbene species. Computational studies also revealed that the rate-limiting step is ene-yne-ketone cyclization, which leads to the formation of the palladium (2-furyl)carbene, while the subsequent carbene migratory insertion is a facile process with a low energy barrier (<5 kcal/mol).
AB - Palladium-catalyzed cross-coupling reactions between benzyl, aryl, or allyl bromides and conjugated ene-yne-ketones lead to the formation of 2-alkenyl-substituted furans. This novel coupling reaction involves oxidative addition, alkyne activation-cyclization, palladium carbene migratory insertion, β-hydride elimination, and catalyst regeneration. Palladium (2-furyl)carbene is proposed as the key intermediate, which is supported by DFT calculations. The palladium carbene character of the key intermediate is validated by three aspects, including bond lengths, Wiberg bond order indices, and molecular orbitals, by comparison to those reported for stable palladium carbene species. Computational studies also revealed that the rate-limiting step is ene-yne-ketone cyclization, which leads to the formation of the palladium (2-furyl)carbene, while the subsequent carbene migratory insertion is a facile process with a low energy barrier (<5 kcal/mol).
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U2 - 10.1021/ja4058844
DO - 10.1021/ja4058844
M3 - Article
C2 - 23947689
AN - SCOPUS:84884196932
SN - 0002-7863
VL - 135
SP - 13502
EP - 13511
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 36
ER -