Zirconium-Catalyzed Synthesis of Alkenylaminoboranes: From a Reliable Preparation of Alkenylboronates to a Direct Stereodivergent Access to Alkenyl Bromides
A simple procedure has been optimized for the preparation of alkenylaminoborane from alkynes using diisopropylaminoborane and HZrCp2Cl. Coupled with a magnesium-catalyzed dehydrogenation, it allowed for the use of air- and moisture-stable diisopropylamine. This synthesis has been extended to a one-pot sequence leading directly to bromoalkenes with controlled stereochemistry. As such, it provides an
[EN] HALOGEN-CONTAINING METATHESIS CATALYSTS AND METHODS THEREOF<br/>[FR] CATALYSEURS DE MÉTATHÈSE CONTENANT DE L'HALOGÈNE ET PROCÉDÉS ASSOCIÉS
申请人:MASSACHUSETTS INST TECHNOLOGY
公开号:WO2018013943A1
公开(公告)日:2018-01-18
The present disclosure provides compounds, compositions, and methods for preparing alkenyl halides and/or haloalkyl-substituted olefins with Z-selectivity. The methods are particularly useful for preparing alkenyl fluorides such as CF3-substituted olefins by means of cross-metathesis reactions using halogen-containing molybdenum and tungsten complexes.
Direct synthesis of Z-alkenyl halides through catalytic cross-metathesis
作者:Ming Joo Koh、Thach T. Nguyen、Hanmo Zhang、Richard R. Schrock、Amir H. Hoveyda
DOI:10.1038/nature17396
日期:2016.3.24
halo-substituted molybdenum alkylidene species are exceptionally reactive and are able to participate in high-yielding olefin metathesisreactions that afford acyclic 1,2-disubstituted Z-alkenyl halides. Transformations are promoted by small amounts of a catalyst that is generated in situ and used with unpurified, commercially available and easy-to-handle liquid 1,2-dihaloethene reagents, and proceed to high
烯烃复分解对现代有机化学产生了很大的影响,但仍然存在重要的缺点:例如,缺乏可用于生成无环烯基卤化物的有效工艺。卤代钌卡宾配合物分解迅速或提供低活性和/或最小的立体选择性,我们对相应的高氧化态系统的理解是有限的。在这里,我们展示了以前未知的卤代钼亚烷基物质具有异常的反应性,并且能够参与提供无环 1,2-二取代 Z-烯基卤化物的高产烯烃复分解反应。原位生成的少量催化剂可促进转化,并与未纯化、市售且易于处理的液体 1,2-二卤代乙烯试剂一起使用,并在四小时内在常温下进行高转化率。我们以高达 91% 的收率和完全的 Z 选择性获得了许多链烯基氯、溴化物和氟化物。该方法可用于轻松合成生物活性化合物,以及对复杂有机分子进行位点和立体选择性氟化。
METHOD FOR PREPARING ALKENYL AMINOBORANES AND THEIR DERIVATIVES, AND USES THEREOF
申请人:UNIVERSITE DE BORDEAUX
公开号:US20220396591A1
公开(公告)日:2022-12-15
Disclosed is a method for preparing alkenyl aminoboranes and their derivatives, and uses thereof. The method for preparing alkenyl aminoboranes includes contacting, preferably in a single synthesis step, a terminal alkyne, an aminoborane and a catalyst chosen from Schwartz's reagent (Cp2ZrHCl), dicyclohexylborane (HBCy), diisopinocamphenylborane (HBipc2) and 9-Borabicyclo(3.3.1)nonane (9-BBN).
The first stereoselective total syntheses of the bioactive marine polyacetylenes (−)-siphonodiol and (−)-tetrahydrosiphonodiol were achieved using highly convergent approaches based on optimized Cadiot−Chodkiewicz and sequential Sonogashira cross-coupling reactions.