Synthesis of Substituted Phosphonates and Their Reactions with Carbonyl Compounds

Abstract

The reaction of the derivatives of 3-phenyl-3-chloro-2-oxopropionic acid with the trivalent phosphorus compounds has been studied. The esterification or amidation of this acid have been shown to influence the course of reaction with Ph₃P. In the reaction with esters enolphosphonium salts are produced, ketophosphonium salts are obtained when amides are involved. Properties of these compounds have also been studied in the Wittig reaction. 3-(α-chlorobenzyl)-2-oxoquinoxaline which reacted with trialkyl phosphates (Arbuzov reaction) has been synthesized. These phosphonates are obtained in nearly quantitative yields, in alkaline conditions (Horner-Emmons reaction) they react smoothly with aromatic aldehydes to give the substituted vinylyuinoxalines.     

Catalytic Asymmetric Hetero-Diels-Alder Reactions of Carbonyl Compounds and Imines

Asymmetric catalysis is a challenge for chemists: How can we design catalysts to achieve the goal of forming optically active compounds? This review provides the reader with an overview of the development of catalytic asymmetric hetero-Diels-Alder reactions of carbonyl compounds and imines. Since its discovery, the Diels-Alder reaction has undergone intensive development and is of fundamental importance for synthetic, physical, and theoretical chemists. The Diels-Alder reaction has been through different stages of development, and at the beginning of the 21st century catalytic Diels-Alder reactions are one of the main areas of focus. The preparation of numerous compounds of importance for our society is based on cycloaddition reactions to carbonyl compounds and imines. There are several parallels between the reactions of carbonyl compounds and those of imines, which, however, begin to vanish on entering the field of catalytic reactions. Why? From a mechanistic point of view some similarities can be drawn, but the synthetic development of catalytic enantioselective hetero-Diels-Alder reactions of imines are several years behind those of the carbonyl compounds. For hetero-Diels-Alder reactions of carbonyl compounds there a number of different chiral catalysts, and great progress has been achieved in developing enantioselective reactions for unactivated and activated carbonyl compounds. In contrast the development of catalytic enantioselective hetero-Diels-Alder reactions of imines is in its infancy and only few catalytic reactions have been published. This review will focus on the most important developments, and discuss the synthetic and mechanistic aspects of enantioselective hetero-Diels-Alder reactions of carbonyl compounds catalyzed by chiral Lewis acids. For the hetero-Diels-Alder reactions of imines, the diastereoselective reactions of optically substrates catalyzed by Lewis acids will be presented first, followed by the catalytic enantioselective reactions.     

二卤卡宾与羰基化合物反应的研究进展

对近年来二卤卡宾与羰基化合物的反应机理研究进行了总结，指出二卤羰基Ｙｉｌｄｅ为反应的中间体，并对影响二卤羰基Ｙｌｉｄｅ的稳定性及后续反应的因素如底物的立体效应，取代基的电子效应，Ｃａｐｔｏｄａｔｉｖｅ效应以卤原子半径大小进行了讨论。     

Catalytic Asymmetric Direct Mannich Reactions of Carbonyl Compounds with alpha-Imino Esters

No AbstractSupporting information for this article is available on the WWW under http://www.angewandte.com or from the author.     

Diethylzinc-Mediated Cross-Coupling Reactions between Dibromoketones and Monobromo Carbonyl Compounds

A novel route to synthesize 1,4-dicarbonyl compounds is described. α,α-Dibromoketones generate zinc enolates through a diethylzinc-mediated halogen-metal exchange and react with α-bromocarbonyl compounds to furnish 1,4-dicarbonyl compounds via a second generation of zinc enolates. This cross-coupling reaction is enabled by the chemoselective formation of zinc enolates from α,α-dibromoketones in the presence of α-bromocarbonyl compounds. Chiral 1,4-dicarbonyl compounds can be obtained via the enantioselective bromination of aldehydes using a chiral secondary amine catalyst and a subsequent cross-coupling reaction between the resulting chiral α-bromoaldehydes and α,α-dibromoacetophenones.     

New Reactions of (2-Aminophenyl)diphenylmethanol with Carbonyl Compounds

Reactions of (2-aminophenyl)diphenylmethanol with ketones (dimedone, camphor, and 3-bromocamphor) in acetic acid result in the formation of arylimines of camphore and 3-bromocamphore, substituted tetrahydroacridin-1(2H)-one and 2-methyl-4,4-diphenylbenzoxazine.     

Condensation of 1,2,4-Butanetriol with Carbonyl Compounds and Reactions of Hydroxyalkyl-1,3-dioxacyclanes

A mixture of isomers of 2-(1,3-dioxolan-4-yl)ethanol and 1,3-dioxan-4-ylmethanol was prepared by reaction of 1,2,4-butanetriol with paraformaldehyde. This mixture was subjected to O-alkylation, O-acylation, condensation with phenyl isocyanate, and substitution of OH groups for Cl. The relative activity of acetone derivatives of glycerol and 1,2,4-butanetriol in reactions with allyl chloride and benzyl chloride was estimated.     

Enzymatic Reactions for the Calorimetric Detection of Phenolic Compounds

This study furnished results on the enzymatic detection of phenolic compounds by means of a miniaturized heat-flow calorimeter (IC-calorimeter). Two enzymes were used: tyrosinase and peroxidase. Additionally to the investigations with the IC-calorimeter, measurements were carried out with a classical reaction calorimeter (LKB 8700) for the very slow reactions with tyrosinase. By way of contrast, the reactions with peroxidase are fast and seem more suitable for sensor application. The detection limit for the investigated phenolic compounds is of the order of 1 mmol l⁻¹ . This revised version was published online in July 2006 with corrections to the Cover Date.     

Chemistry of Azobenzazole Systems. 3. Reactions of 2-Hydrazinobenzoxazole with Carbonyl Compounds

The reaction of 2-hydrazinobenzoxazole with various carbonyl compounds was studied. Only the corresponding azides were obtained with acylating agents such as acid anhydrides and acid chlorides and products with a fused triazole ring were not obtained. Only the corresponding hydrazones were obtained from furfural and 2-carboxy-3,4-dimethoxybenzaldehyde.     

One-Pot Formation of Carbonates from the Reactions of Carbonyl Compounds with Samarium Diiodide and Methyl Chloroformate

Treatment of carbonyl compounds with SmI₂ and methyl chloroformate in the presence of molecular sieves provides the cyclic carbonates or biscarbonates of pinacols. This one-pot reaction proceeds rapidly even with aliphatic ketones. The stereochemistry obtained by this procedure is different from that of conventional pinacolic couplings.     

The Forgotten Carbonyl Reaction: Chloroacetylation and Bromoacetylation of Carbonyl Compounds

Halomethyl acetates ( 3 ) could be prepared from aliphatic, α,β‐unsaturated and aromatic aldehydes, as well as from alicyclic ketones with high yields in simple one‐pot reactions. Very often, the products didn't have to be purified and could directly be used for synthetic purposes after evaporation of the solvent. Obviously, the ‘bad reputation’ of the reaction in the literature stemed from the fact that the reactions didn't take place under the best conditions. Carbonyl compounds ( 1 ) and acyl halides ( 2 ) form equilibria which are completely on the side of the halomethyl acetates ( 3 ) at room temperature (starting with aliphatic and most aromatic aldehydes) and which can be strongly influenced by the reaction parameters. It is crucial to work at low temperature in apolar solvents and to remove (or deactivate) the catalyst before workup. Reactions may be realized with or without solvents. Side reactions were observed with formaldehyde and acetaldehyde but, with exception of formaldehyde, could be reduced close to zero (see Fig. 5). By‐products were essentially avoided if the reaction took place in apolar solvents and with a local excess of acetyl chloride. In many cases clean products were available which could directly be used for synthetic purposes. Halomethyl acetates ( 3 ) are bifunctional carbonyl derivatives with two different leaving groups, whose preparative advantages have been useful for the synthesis of various pentafulvenes, but were especially important for preparing unstable parent fulvenes and fulvalenes.     

金属化的苄叉基膦叶立德与羰基化合物的Wittig反应的立体化学

首次系统报道了金属化的苄叉二苯基膦烷与芳香醛、酮的Wittig的立体化学，与相应的单叶立德相比，反应具有高的立体选择性、反应活性和较好的原子经济性的优点。