Dehydrative Direct CH Allylation with Allylic Alcohols under [Cp*Co
<sup>III</sup>
] Catalysis
作者:Yudai Suzuki、Bo Sun、Ken Sakata、Tatsuhiko Yoshino、Shigeki Matsunaga、Motomu Kanai
DOI:10.1002/anie.201503704
日期:2015.8.17
dehydrative CH allylation with non‐activated allyl alcohols, thus giving C2‐allylated indoles, pyrrole, and phenyl‐pyrazole in good yields, while analogous [Cp*RhIII] catalysts were not effective. The high γ‐selectivity and C2‐selectivity indicated that the reaction proceeded by directing‐group‐assisted CH metalation. DFT calculations suggested that the γ‐selective substitution reaction proceeded by CH metalation
证明了[Cp * Co III ]相对于[Cp * Rh III ]的独特反应性。阳离子型[Cp * Co III ]催化剂可促进未活化的烯丙醇直接脱水使CH烯丙基化,从而获得高收率的C2烯丙基化的吲哚,吡咯和苯基吡唑,而类似的[Cp * Rh III ]催化剂是没有效果。较高的γ选择性和C2选择性表明该反应是通过引导基团辅助的CH金属化而进行的。DFT计算表明,通过CH金属化和插入CC双键进行了γ-选择性取代反应,随后消除了β-氢氧根。[Cp * CoIII ]催化剂比β-氢化物的消除更有利于β-氢氧化物的消除。