Preferential Bond Activation of sp<sup>3</sup>C–H over sp<sup>2</sup>C–H in<i>α,β</i>-Unsaturated Carboxylic Acids by Ruthenium Complex
作者:Susumu Kanaya、Nobuyuki Komine、Masafumi Hirano、Sanshiro Komiya
DOI:10.1246/cl.2001.1284
日期:2001.12
Reactions of Ru(1,5-cod)(1,3,5-cot) (1)/Pme3 [cod = cyclooctadiene, cot = cyclooctatriene] with propenoic acids (CH2=CH(R)COOH) give unsaturated ruthenalactones Ru[OC(O)C(R)=CH-κ2O,C](Pme3)4 [R = Me (2a), Et (2b), Pr (2c), iPr (2d)]. In contrast, reactions of trans-2-methyl-2-butenoic acid and 2-methylcinnamic acid (R′CH=C(Me)COOH) give Ru[OC(O)C(CH2R′)=CH-κ2O,C](Pme3)4 [R′ = Me (2b), Ph (2e)] as major products, suggesting the preferential activation of the sp3 C–H over sp2 C–H bond on ruthenium(II) center.
Ru(1,5-cod)(1,3,5-cot) (1)/Pme3 [cod = 环辛二烯,cot = 环辛三烯] 与丙烯酸(CH2=CH(R)COOH)反应生成不饱和钌内酯 Ru[OC(O)C(R)=CH-κ2O,C](Pme3)4 [R = Me (2a),Et (2b),Pr (2c),iPr (2d)]。相反,反式-2-甲基-2-丁烯酸和 2-甲基肉桂酸(R′CH=C(Me)COOH)反应的主要产物是 Ru[OC(O)C(CH2R′)=CH-κ2O,C](Pme3)4 [R′ = Me (2b)、Ph (2e)],这表明钌(II)中心上的 sp3 C-H 键比 sp2 C-H 键优先活化。