3-Chloroalkylfurans in the reaction with sodium diethyl phosphite
摘要:
Reduction of 3-acylfurans with lithium alumohydride in ether yields stable secondary alcohols. By treatment with thionyl chloride in the presence of pyridine, they are converted to the corresponding chlorides. 3-(1-Chloroethyl)furan and 5-methyl-3-(1-chloroethyl)furan react with sodium diethyl phosphite to give two products: 3-(1-diethoxyphosphoryiethyl)furans and 3-ethyl-2-(diethoxyphosphoryloxy)furans. The methyl group in position 5 of the furan ring increases the relative phosphate content of the mixture by a factor of approximately 2.5. Blocking of position 2 or both positions 2 and 5 of the ring with methyl groups leads to phosphonate formation only. The reaction of 2,5-dimethyl-3-(1-chloro-2-methylpropyl)furan also occurs according to the Michaelis-Becker scheme. The products of the side chain dehydrohalogenation with sodium diethyl phosphite were not found.
在这里,我们报告了一种有效的铑催化酮脱氧硼酸化合成烷基硼酸酯,其中区域选择性可以通过选择配体来切换。直链烷基硼酸酯仅在 P( n Bu) 3存在下获得,PPh 2 Me 有利于支链烷基硼酸酯的形成。该协议还允许从现成的酮中获取 1,1,2-三硼酸酯。机理研究表明,这种 Rh 催化的酮类脱氧硼酸化反应经过烯烃中间体,该中间体经历区域发散硼氢化反应,得到直链和支链烷基硼酸酯。PPh 2 Me 和 P( n Bu) 3的不同空间位阻效应通过密度泛函理论计算发现是产物选择性的原因。烯烃中间体也可以依次进行脱氢硼酸化和硼氢化反应以提供三硼酸酯。
Hydrosilylation of aldehydes and ketones catalysed by nickel acetate and tricyclohexylphosphine as the catalytic system was demonstrated using polymethylhydrosiloxane as a cheap reducing reagent.
使用聚甲基氢硅氧烷作为廉价还原剂,展示了由乙酸镍和三环己基膦组成的催化系统催化醛和酮的氢硅化反应。
Hydrosilylation of Aldehydes and Ketones Catalyzed by an N-Heterocyclic Carbene-Nickel Hydride Complex under Mild Conditions
作者:Linus P. Bheeter、Mickaël Henrion、Lydia Brelot、Christophe Darcel、Michael J. Chetcuti、Jean-Baptiste Sortais、Vincent Ritleng
DOI:10.1002/adsc.201200460
日期:2012.10.8
Half-sandwich N-heterocyclic carbene (NHC)-nickel complexes of the general formula [Ni(NHC)ClCp†] (Cp†=Cp, Cp*) efficiently catalyze the hydrosilylation of aldehydes and ketones at room temperature in the presence of a catalytic amount of sodium triethylborohydride and thus join the fairly exclusive club of well-defined nickel(II) catalyst precursors for the hydrosilylation of carbonyl functionalities
Electroorganic Synthesis of 2,5-Dialkoxydihydrofurans and Pyridazines on Solid Phase Using Polymer Beads as Supports
作者:Rolf Breinbauer、Sukanya Nad
DOI:10.1055/s-2005-918493
日期:——
by the use of a redox mediator which shuttles electrons from the electrode to the polymer bound substrate molecules. This approach of indirect electroorganic synthesis was successfully applied for the 2,5-dialkoxylation of furans on solidphase. The oxidation products can be hydroly/ed and through condensation with hydrazine hydrate substituted pyridazines are produced in 50-65% overall yield.
available ketones. Mechanistic studies suggest that this Rh-catalyzed deoxygenative borylation of ketones goes through an alkene intermediate, which undergoes regiodivergent hydroboration to afford linear and branched alkylboronates. The different steric effects of PPh2Me and P(nBu)3 were found to be responsible for product selectivity by density functional theory calculations. The alkene intermediate
在这里,我们报告了一种有效的铑催化酮脱氧硼酸化合成烷基硼酸酯,其中区域选择性可以通过选择配体来切换。直链烷基硼酸酯仅在 P( n Bu) 3存在下获得,PPh 2 Me 有利于支链烷基硼酸酯的形成。该协议还允许从现成的酮中获取 1,1,2-三硼酸酯。机理研究表明,这种 Rh 催化的酮类脱氧硼酸化反应经过烯烃中间体,该中间体经历区域发散硼氢化反应,得到直链和支链烷基硼酸酯。PPh 2 Me 和 P( n Bu) 3的不同空间位阻效应通过密度泛函理论计算发现是产物选择性的原因。烯烃中间体也可以依次进行脱氢硼酸化和硼氢化反应以提供三硼酸酯。