Intermolecular Alkyne Hydroacylation. Mechanistic Insight from the Isolation of the Vinyl Intermediate That Precedes Reductive Elimination
作者:Rebekah J. Pawley、Miguel A. Huertos、Guy C. Lloyd-Jones、Andrew S. Weller、Michael C. Willis
DOI:10.1021/om300647n
日期:2012.8.13
occur via a metallocyclopropene intermediate. During catalysis, the consumption of substrates and evolution of products follow pseudo zero-order kinetics. The observation of both linear and branched products under stoichiometric and catalytic regimes, in combination with kinetic modeling, allows for an overall mechanistic scheme to be presented. Partitioning of linear and branched pathways at the hydride
支链链烯基中间直接先于最终的α还原消除的隔离,β不饱和酮产物被报告炔HC≡CAr之间的加氢酰化反应˚F(AR ˚F = 3,5-(CF 3)2 C ^ 6 ħ 3)和β-S-取代的醛2-(甲硫基)苯甲醛:的[Rh(FAC -κ 3 -DPEphos)(C(= CH 2)中的Ar ˚F)(C(O)C 6 H ^ 4 SME)2 ] [CB 11 H 12]。该中间体的结构表明,至少在该系统中,发生了氢化物迁移而不是酰基迁移。对后续的还原消除动力学研究,以形成晶体学表征酮结合的产物的[Rh(顺-κ 2 -DPEphos)(η 2:η 2,κ 1 -H 2 C = C(AR ˚F)C(= O) (C 6 H ^ 4 SME)] [CB 11 H ^ 12 ]产生以下激活参数还原消除,它遵循一级动力学(ķ OBS =(6.14±0.04)×10 -5小号-1,324 K): ΔH⧧ = 95±2 kJ