Deacylative Allylation: Allylic Alkylation via Retro-Claisen Activation
作者:Alexander J. Grenning、Jon A. Tunge
DOI:10.1021/ja205717f
日期:2011.9.21
"deacylative allylation", the coupling partners, an allylic alcohol and a ketone pronucleophile, undergo in situ retro-Claisen activation to generate an allylic acetate and a carbanion. In the presence of palladium, these reactive intermediates undergo catalytic coupling to form a new C-C bond. In comparison to unimolecular decarboxylative allylation, a commonly utilized method for allylation of carbon
本文描述了多种相对不稳定的碳亲核试剂的烯丙基烷基化的新方法。在这个“脱酰基烯丙基化”过程中,偶联伙伴,烯丙醇和酮亲核试剂,进行原位逆克莱森活化以生成烯丙乙酸和碳负离子。在钯的存在下,这些反应性中间体进行催化偶联形成新的 CC 键。与单分子脱羧烯丙基化(一种常用的碳阴离子烯丙基化方法)相比,脱酰基烯丙基化是一种分子间过程。此外,脱酰基烯丙基化允许容易获得的烯丙醇直接偶联。最后,通过快速构建多种 1、
The salt-free nickel-catalysed α-allylation reaction of ketones with allyl alcohol and diallylether
The nickel-catalysed α-allylation of ketones with allylalcohol and diallylether has been performed under neutral conditions. As no base is involved, the products are synthesized without salts as side products. The dppf/Ni(cod)2 catalytic system in MeOH at 80 °C has been shown as the most effective reaction system to afford tetrasubstituted derivatives from various cyclic and acyclic ketones with one
The benzylation of a set of nine ketones provides enough information to establish how the ketone structure affects the existence of a pi-pi interaction. The presence of a phenyl moiety starting from the alpha-carbon atom and flexibility in cyclic ketones are structural features required for effective interactions. The pi-pi interaction is controlled by a polar-pi effect. Stronger interaction is achieved when slight electronwithdrawing groups are present in both pi-system. This results is explained by the predominance of the sigma-pi shells attractive interaction in an edge-to-face geometry. (C) 1997 Elsevier Science Ltd.