The half‐sandwich titanocene CpTi
<sup>III</sup>
Cl
<sub>2</sub>
as efficient system for the preparation of 2,5‐dihydrofurans
<i>via</i>
α‐allenols
作者:Irene Torres‐García、Josefa L. López‐Martínez、Raquel Martínez‐Martínez、J. Enrique Oltra、Manuel Muñoz‐Dorado、Ignacio Rodríguez‐García、Miriam Álvarez‐Corral
DOI:10.1002/aoc.5244
日期:2020.1
excellent system for the Barbier‐type reaction between aldehydes and propargylic halides, leading to homopropargylic alcohols and α‐allenols. An efficient and straightforward methodology for the conversion of aldehydes into 2,5‐dihydrofurans involving a two‐step sequence (TiIII addition‐AgI cyclization) is presented. The usefulness of the method is proved by the preparation of a Natural Product: a dihydrofuranic
半夹心钛茂试剂CpTi III Cl 2是通过用锰原位还原商用CpTiCl 3而获得的,它是醛与炔丙基卤化物之间的Barbier型反应的极佳系统,可导致均炔丙基醇和α-烯丙醇。提出了一种高效,直接的方法,将醛转化为2,5-二氢呋喃涉及两个步骤(Ti III加成-Ag I环化)。该方法的有用性通过制备天然产物:从Mikania sp。的叶子中分离出来的二氢呋喃丹丹证明。十一月
A simple and efficient synthesis of chlorotetrolic esters
作者:Martin Olomucki、Jean-Yves le Gall、Isabelle Barrand
DOI:10.1039/c39820001290
日期:——
Treatment of propargyl chloride with methyl-lithium and an excess of alkyl chloroformate leads to chlorotetrolicesters in an average yield of 65%, in contrast with the previously reported three-step, low-yield synthesis of these biochemical reagents.
Palladium Pincer Complex Catalyzed Stannyl and Silyl Transfer to Propargylic Substrates: Synthetic Scope and Mechanism
作者:Johan Kjellgren、Henrik Sundén、Kálmán J. Szabó
DOI:10.1021/ja043951b
日期:2005.2.1
corresponding pincer complex catalyst. DFT modeling studies have shown that the trimethylstannyl functionality is transferred to the propargylic substrate in a single reaction step with high allenyl selectivity. Inspection of the TS structures reveals that the trimethylstannyl group transfer is initiated by the attack of the palladium-tin sigma-bond electrons on the propargylic substrate. This is a novel
Palladium Pincer Complex-Catalyzed Trimethyltin Substitution of Functionalized Propargylic Substrates. An Efficient Route to Propargyl- and Allenyl-Stannanes
作者:Johan Kjellgren、Henrik Sundén、Kálmán J. Szabó
DOI:10.1021/ja0391715
日期:2004.1.1
effects of the propargylicsubstrate: electron-withdrawing functionalities give mainly allenyl stannane products, while with electron-donating groups the main product is propargyl stannane. The catalytic reaction proceeds under very mild conditions tolerating many functionalities such as OH, OAc, NR3, and NR2Ac groups. Our mechanistic studies indicate that the key intermediate of the reaction is a monotrimethylstannane