Heck Reactions Starting from Silyl Enol Ethers - A Simple One-Pot Nonaflation-Coupling Procedure for the Synthesis of 1,3-Dienes
作者:Matthias Webel、Hans-Ulrich Reissig
DOI:10.1055/s-1997-976
日期:1997.10
Starting from silyl enol ether 4 the corresponding alkenylnonaflate 5 was generated by treatment with nonafluorobutanesulfonyl fluoride (NfF) and a catalytic amount of tetra-n-butyl-ammonium fluoride (TBAF). By Pd-catalysis 5 was directly Heck-coupled with a variety of olefins to furnish functionalized 1,3-dienes 6 - 12. This one-pot procedure could be extended to other silyl enol ethers and provides new synthetic options.
catalysts for this process. The reaction allows the synthesis of a wide variety of cyclic and acyclic alkenyl nonaflates 3 in good to excellent yields. For E/Z isomeric alkenes the configuration of the double bond is essentially retained. Remarkably, enolates derived from methyl ketones also provide C-sulfonylation products 4 as a side product; the desired alkenyl nonaflates 3l and 3m could, however, be prepared
An Expedient Variant of Heck Reaction of Alkenyl Nonaflates: Homogeneous Ligand-Free Palladium Catalysis at Room Temperature
作者:Michael A. K. Vogel、Christian B. W. Stark、Ilya M. Lyapkalo
DOI:10.1002/adsc.200600388
日期:2007.5.7
represents a remarkably robust, active and efficient catalyticsystem generally applicable to the coupling with a broad range of terminal olefins including non-activated ones under ambient conditions. It features insensitivity towards atmospheric oxygen and moisture, furnishing uniformly high yields of the anticipated coupling products without the necessity to purify commercial reagents and solvents.
A Straightforward Synthesis of Alkenyl Nonaflates from Carbonyl Compounds Using Nonafluorobutane-1-sulfonyl Fluoride in Combination with Phosphazene Bases
作者:Ilya Lyapkalo、Michael Vogel、Christian Stark
DOI:10.1055/s-2007-991084
日期:——
nonafluorobutane-1-sulfonyl fluoride furnishes the corresponding alkenyl nonaflates. The new general method provides high yields of alkenyl nonaflates from aldehydes and cyclic ketones. However, it is not applicable to acyclicketones whose nonaflate derivatives undergo fast E2 elimination to give alkynes. Successful synthesis of nonaflates from aldehydes requires carefully controlled reaction conditions to avoid
在内部淬灭剂九氟丁烷-1-磺酰氟的存在下,羰基化合物与磷腈碱的 α-去质子化提供相应的烯基九氟甲磺酸酯。新的通用方法从醛和环酮中提供了高产率的烯基壬二酸酯。然而,它不适用于非环酮,其九氟甲磺酸酯衍生物经过快速 E2 消除得到炔烃。由醛成功合成九氟甲磺酸酯需要仔细控制反应条件,以避免随后消除为炔烃。动力学控制能够实现高区域选择性,有利于衍生自环酮的最少取代的九氟甲磺酸酯区域异构体和衍生自醛的烯基九氟甲磺酸酯的适度 Z 选择性。
Synthesis of Highly Functionalized Tri- and Tetrasubstituted Alkenes via Pd-Catalyzed 1,2-Hydrovinylation of Terminal 1,3-Dienes
作者:Vaneet Saini、Mark O’Dair、Matthew S. Sigman
DOI:10.1021/ja511640g
日期:2015.1.21
An efficient method for the construction of Csp2–Csp3 bond in a regio- and stereoselective fashion involving 1,3-terminal dienes, enol triflates/nonaflates, and sodium formate under Pd(0)-catalysis is described. The three component assembly allows trapping of a π-allyl intermediate, after the initial migratory insertion of the diene, by a hydride source that leads to structurally complex and synthetically