Visible-Light-Promoted Redox-Neutral Cyclopropanation Reactions of α-Substituted Vinylphosphonates and Other Michael Acceptors with Chloromethyl Silicate as Methylene Transfer Reagent
with chloromethyl silicate as a methylene transfer reagent has been accomplished via visible‐light‐mediated redox‐neutral catalysis. This method features broad functional group tolerance and mild conditions. In addition to α‐substituted vinylphosphonates, a range of Michael acceptors including α,β‐unsaturated acrylate, ketone, amide and sulfone are suitable substrates for this photocatalytic cyclopropanation
The first palladium‐catalyzed method for the arylation of α‐phosphonovinyl nonaflates is described. Using a catalyst comprised of Pd(OAc)2 and SPhos, terminal and internal α‐aryl vinylphosphonates could be efficiently accessed under mild conditions. The reaction features a broad coupling partner scope and tolerates many functional groups.
Base mediated 1,3-dipolar cycloaddition of α-substituted vinyl phosphonates with diazo compounds for synthesis of 3-pyrazolylphosphonates and 5-pyrazolcarboxylates
作者:Nataliya S. Goulioukina、Nikolay N. Makukhin、Egor D. Shinkarev、Yuri K. Grishin、Vitaly A. Roznyatovsky、Irina P. Beletskaya
DOI:10.1039/c6ob01780k
日期:——
5-Aryl-substituted pyrazol-3-ylphosphonates have been conveniently synthesized by 1,3-dipolar cycloaddition of 1-formamidovinylphosphonates and aryldiazomethanes under K2CO3/MeOH conditions at room temperature. These pyrazoles are formed in one pot via spontaneous elimination of formamide. Basic conditions prevent competitive formation of cyclopropylphosphonates. 3-Aryl substituted pyrazol-5-carboxylates
通过在室温下在K 2 CO 3 / MeOH条件下将1-甲酰胺基乙烯基膦酸酯和芳基重氮甲烷进行1,3-偶极环加成,可以方便地合成5-芳基取代的吡唑-3-基膦酸酯。这些吡唑是通过自发消除甲酰胺而在一锅中形成的。碱性条件阻止竞争性形成环丙基膦酸酯。3-芳基取代的吡唑-5-羧酸酯可以通过相同的方法由1-芳基乙烯基膦酸酯和重氮乙酸乙酯合成,尽管为了确保芳构化阶段成功且消除二乙氧基磷酰基部分是必需的,更强的碱NaH是必需的。
Metal-free diimide reduction of alkenylphosphonates: simple and efficient protocol for the synthesis of α-substituted ethylphosphonates
A simple and straightforward method for the synthesis of α-substituted ethylphosphonates via diimide reduction strategy is described. With K3PO4 or Na2CO3 as the basic additive, a range of terminal alkenylphosphonates underwent efficient reduction by diimide generated from 2-nitrobenzenesulfonylhydrazide (NBSH) under room temperature. The high functional group tolerance of this methodology is also
描述了一种通过二酰亚胺还原策略合成α-取代的乙基膦酸酯的简单直接的方法。以K 3 PO 4或Na 2 CO 3为基本添加剂,在室温下,一定范围内的末端链烯基膦酸酯被2-硝基苯磺酰肼(NBSH)生成的二酰亚胺有效还原。还证明了该方法具有较高的官能团耐受性。此外,我们的方法具有安全性高,反应条件温和,对设备的要求低以及化学选择性高的特点。
Efficient synthesis of α-substituted ethylphosphonates via CuH-catalyzed conjugate reduction of terminal alkenylphosphonate
An unprecedented approach toward synthesis of α-substituted ethylphosphonates based on CuH-catalyzed conjugate reduction of vinylphosphonates has been successfully developed. This protocol features mild conditions, broad substrate scope, good functional group compatibility, high overall efficiencies, and easy gram-scale synthesis. The Cu-catalyzed reduction takes place in a highly selective manner