CAN Catalyzed One‐Pot Synthesis of α‐Amino Phosphonates from Carbonyl Compounds

Abstract

α‐Amino phosphonates are synthesized by three component condensation of aldehydes, amines, and diethyl phosphite using ceric ammonium nitrate at room temperature to afford the corresponding α‐amino phosphonates in high yields.     

Iron Carbonyl Induced Reactions of Norbornene Derivatives with Substituted Acetylenes

Photochemical reactions of norbornadiene with substituted acetylenes in the presence of Fe(CO)₅ gave various products of different types, depending on the nature of the acetylene. The results are summarized in Table 1. The cyclopentanone 1 was always formed in these reactions. In the reaction of disubstituted acetylenes such as dimethyl acetylenedicarboxylate and ethyl phenylpropiolate, the cyclopentenones 2 and 5 were formed, respectively. By contrast, propiolic esters produced the cyclohexenones 3 and 4 , in which the ester group was attached on the β carbon with respect to the keto group. Plausible mechanisms for the formation of these products are shown in Schemes 7 and 8. The reaction of diphenylacetylene gave the cyclohexendione 7 as well as the cyclopentenone 6 . Two enedione products 8 and 9 were obtained from the reaction of phenylacetylene. Compound 9 was converted to the aromatic diacetate 13 by heating with acetic anhydride in pyridine. On irradiation in the presence of Fe(CO)₅ norbornene reacted similarly with dimethyl acetylenedicarboxylate and phenylacetylene to give the cyclopentenone 14 and the cyclohexenone 15 , respectively. Compound 15 , upon heating, isomerized to hydroquinone 16 , which on acetylation gave the diacetate 17 .     

Substituted Phosphonates and Diphosphonates: The Synthesis Strategy

Russian Journal of General Chemistry -     

Synthesis of Arylnaphthoquinones and Their Reactions with o‐Substituted Primary Aromatic Amines

Cycloaddition reaction of 2‐aryl‐1,4‐benzoquinones 1a‐d with a number of different dienes, namely 2,3‐dimethylbutadiene; 1,4‐diphenylbutadiene and anthracene yield 2‐aryl‐6,7‐dimethyl‐1,4‐ naphthoquinones 3a,b ; 2,5,8‐triphenyl‐1,4‐naphthoquinone 4 and 2‐aryl‐1,4,9,10‐tetrahydro‐9,10‐o‐benzoanthracene‐1,4‐dione 5 , respectively were investigated. In addition, the cycloaddition reaction of 2‐aryl‐1,4‐benzoquinones 1d,e with 2,3‐dimethylbutadiene was also investigated to yield 2‐aryl‐5,8‐dihydro‐6,7‐dimethyl‐1,4‐naphthohydroquinones 2a,b . Cyclocondensation reactions of Diels‐Alder adducts 2b, 3b, 5a with ethylenediamine, o‐substituted primary aromatic amines gave quinoxaline, phenazine, phenoxazine and phenothiazine ocyclic derivatives 6–14.     

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.     

Synthesis and Characterization of Manganese Carbonyl Compounds with PNP

Attheendof1930s,ThesynthesisofMn(C6H6)21firstreportedbyH.Gilmanattractedmuchattention.Subsequently,manyneworgano-manganesecompoundshavebeensythesized.Inthe1950s,itwasfoundthatCPMn(CO)3andsomeofitSderivativesaughtactastheantiknockofgasolinetosubstitutetetra-ethylleadwhichisveryharmfultoourenvironment.Thisfindinghasattractedpeople'sinterestinthestudyofthisfield.Inthiswork,weobtainedtwonewcompoundsthroughthesubstitutionreactionbetweenmixeddonorphosphineligand2,6-di(hi-phenylphosphine)pyridme…     

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。     

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.     

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.     

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.     

Transition Metal Catalysts in the Synthesis of Functionalized Substituted Phosphonates

Abstract

Synthesis of new functionalized phosphonates was achieved by two ways, using either nucleophilic or electrophilic modification of organophosphorus compounds by transition metal catalytic reactions The first way employs the transformation of carbonyl group in α, β, and y-ketophosphonates by nucleophilic addition (silacyanation, hydrosilylation, etc).     

Continuous-Flow Synthesis of Arylthio-Cyclopropyl Carbonyl Compounds

The straightforward, continuous-flow synthesis of cyclopropyl carbaldehydes and ketones has been developed starting from 2-hydroxycyclobutanones and aryl thiols. This acid-catalyzed mediated procedure allows access to the multigram and easily scalable synthesis of cyclopropyl adducts under mild conditions, using reusable Amberlyst-35 as a catalyst. The resins, suitably ground and used for filling steel columns, have been characterized via TGA, ATR, SEM and BET analyses to describe the physical–chemical properties of the packed bed and the continuous-flow system in detail. To highlight the synthetic versatility of the arylthiocyclopropyl carbonyl compounds, a series of selective oxidation reactions have been performed to access sulfoxide and sulfone carbaldehyde cyclopropanes, oxiranes and carboxylic acid derivatives.     

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.     

Reactions of CpCuPPh3 with Lanthanides and Their Compounds

CpCuPPh₃ reacts with Pr, Er, Yb, Cp₂Yb, and SmI₂(THF)₄ to form, in high yields, lanthanide cyclopentadienyl derivatives Cp₂Yb, Cp₃Ln (Ln = Pr, Er, Yb), and CpSmI₂(THF)₂. The initial agent CpCuPPh₃ can be prepared in 95-98% yield by the reaction of t-BuOCu with CpH in the presence of PPh₃.     

Synthesis and Reactions of Phosphorus Substituted Acetylenes

Abstract

To construct phosphorus-functional group substituted Ir-electron systems, synthesis of acetylenes possessing phosphorus substituents and the reactions with CpCo(CO)₂ were investigated.     

Synthesis of Substituted Heterocyclic Thiourea Compounds

Heterocyclic thioureas having multiple substitutions were prepared in two steps with overall yields of 60–80%. Condensation of a substituted heterocyclic amine with thiocarbonyldiimidazole, followed by treatment with a disubstituted phenylethylamine in dimethyl formamide (DMF), yielded the desired heterocyclic thioureas as crystalline solids.