Dehydrative Direct C-H Allylation with Allylic Alcohols under [Cp*Co(III)] Catalysis.
Dehydrative Direct C-H Allylation with Allylic Alcohols under [Cp*Co(III)] Catalysis.
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DOI：
10.1002/anie.201503704
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发表时间：
2015-08
影响因子：
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通讯作者：
Yudai Suzuki;Bo Sun;Ken Sakata;Tatsuhiko Yoshino;S. Matsunaga;M. Kanai
中科院分区：
文献类型：
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作者：
Yudai Suzuki;Bo Sun;Ken Sakata;Tatsuhiko Yoshino;S. Matsunaga;M. Kanai
证明了[Cp*Co(III)]对[Cp*Rh(III)]的独特反应性。阳离子[Cp*Co(III)]催化剂促进了C-H与非活化烯丙醇的直接脱水烯丙基化反应，从而得到c2 -烯丙基化的吲哚、吡咯和苯基吡唑，收率较高，而类似的[Cp*Rh(III)]催化剂效果不佳。高γ-选择性和c2选择性表明反应是由导向基团辅助的C-H金属化反应进行的。DFT计算表明，γ-选择性取代反应通过C-H金属化和C-C双键的插入进行，随后β-氢氧化物消除。[Cp*Co(III)]催化剂有利于β-氢化物的消除，而不是β-氢化物的消除。
The unique reactivity of [Cp*Co(III)] over [Cp*Rh(III)] was demonstrated. A cationic [Cp*Co(III)] catalyst promoted direct dehydrative C-H allylation with non-activated allyl alcohols, thus giving C2-allylated indoles, pyrrole, and phenyl-pyrazole in good yields, while analogous [Cp*Rh(III)] catalysts were not effective. The high γ-selectivity and C2-selectivity indicated that the reaction proceeded by directing-group-assisted C-H metalation. DFT calculations suggested that the γ-selective substitution reaction proceeded by C-H metalation and insertion of a C-C double bond, with subsequent β-hydroxide elimination. The [Cp*Co(III)] catalyst favored β-hydroxide elimination over β-hydride elimination.