Barbier-type Reaction Research Articles

Indium and zinc mediated Barbier type reactions: Allylation and propargylation reactions of 6-oxopenicillanate and 7-oxocephalosporanate

Allylation and propargylation of compounds, 6-oxopenicillanate 1 and 7-oxocephalosporanate 2, were accomplished by reacting the corresponding bromides in the presence of indium or zinc. Both indium and zinc gave alkylated products in moderate yields under mild conditions. Indium mediated Barbier reactions in aqueous THF exhibited slightly higher stereoselectivity than zinc mediated reactions in anhydrous THF.

Barbier-Type Reactions of Cyclic Acid Anhydrides and Keto Acids Mediated by an SmI2-(NiI2-Catalytic) System – Preparation of Disubstituted Lactones

Cyclic acid anhydrides (succinic and glutaric anhydrides and some of their derivatives) undergo fast Barbier-type reactions mediated by samarium diiodide in the presence of catalytic amounts of nickel diiodide (1 mol-% with respect to SmI2), to give disubstituted lactones in high yields. Without NiI2 no reaction occurs. Various alkyl and allyl iodides can be used. In these reactions the formation of a samarium keto carboxylate intermediate is likely; as a matter of fact, keto carboxylic acids react under similar conditions to also yield disubstituted lactones. It is demonstrated that lactonisation occurs during hydrolysis of the reaction.

Organofluorine Compounds and Fluorinating Agents; 20: The Nucleophilic Perfluoroalkylation of Sugar Aldehydes Using a Sonochemical Barbier-Type Reaction

Organofluorine Compounds and Fluorinating Agents; 20: The Nucleophilic Perfluoroalkylation of Sugar Aldehydes Using a Sonochemical Barbier-Type Reaction

Convenient Access to Primary Amines by Employing the Barbier-Type Reaction of N-(Trimethylsilyl)imines Derived from Aromatic and Aliphatic Aldehydes

A new versatile preparation of primary amines via benzylation of aromatic and aliphatic aldimines is described. Sonochemical and traditional methods for generation of the reactive intermediates are compared and contrasted. Competitive reactions were analyzed via free energy relationships to support the proposed alkylative mechanism.

Synthesis of homoallylic (but-3-enylic) alcohols from aldehydes with allylic chlorides, tin(II) chloride and potassium iodide in water

Homoallylic (but-3-enylic) alcohols have been prepared in good yields by reductive allylation of aldehydes in water with various allylic chlorides in the presence of tin(II) chloride and potassium iodide. The Barbier type reaction with prop-2-ynyl chloride is also achieved under the same conditions.

Naphthalene-catalysed lithiation of carbamoyl and thiocarbamoyl chlorides under Barbier-type reaction conditions

The reaction of different carbamoyl or thiocarbamoyl chlorides 1 with carbonyl compounds or imines 2 in the presence of an excess of lithium powder and a catalytic amount of naphthalene (3 mol %) in THF at −78°C leads, after hydrolysis with water, to the expected α-hydroxy or α-amino amides 3, respectively. In the case of allylic or benzylic derivatives 1a,c, when longer reaction times are used, the corresponding products 4 resulting from a deallylation or debenzylation are obtained. The use of DMF or phenyl isocyanate as electrophiles affords substituted oxamides 5. Finally, when previously to the hydrolysis an excess of an alkyl chloride is added to the reaction mixture, 1,2-diols 6 are formed, resulting from a final double addition of the in situ generated alkyllithium to the α-hydroxy amide initially formed.

A Barbier type reaction promoted by in situ formed active metal bismuth from NaBH4 and BiCl3 in aqueous media

AbstractIn the presence of active metal bismuth (Bi*) which was prepared from the combination of bismuth trichloride and sodium borohydride, aldehydes have been found to react with allyl bromide in aqueous media, and the corresponding homoallylic alcohols were obtained in excellent yields with high chemo‐and stereoselectivity.

Active metals prepared in liquid ammonia. Zinc and tin-promoted synthesis of β-hydroxyesters, homoallylic and homopropargylic alcohols

Active zinc and tin powder can be prepared by reduction of ZnCl 2 and SnCl 2 with sodium in tetrahydrofuran-liquid ammonia mixtures of various compositions. The activity of the reduced zinc depends on concentration of ammonia in the reaction medium. Zinc (A) prepared in liquid ammonia (Method A) was much less active then zinc (B) prepared in THF containing 10–20 volume % of liquid ammonia (Method B). The X-ray powder diffractometry data suggested that zinc (B) was less crystalline then zinc (A). The Reformatsky and Barbier type reactions of carbonyl compounds with α-bromoesters, allylic and propargylic bromides in the presence of Zn or Sn prepared by method B gave the corresponding β-hydroxyesters, homoallylic and homopropargylic alcohols in good to excellent yields.

A simple and highly efficient preparation of arylstannane via sonochemical barbier reaction

Arylstannane is produced by a reaction of aryl bromide, magnesium powder, 1,2-dibromoethane and bis(tributyltin)oxide via sonochemical Barbier-type reaction in a commercial ultrasonic cleaning bath (39 kHz).

Preparation of active zinc by reduction of zinc chloride with sodium in liquid ammonia and its use in the barbier reaction

Active zine powder produced by reduction of anhydrous zine chloride with solution of sodium in liquid ammonia exhibits high reactivity in the Barbier type reaction both in THF and liquid ammonia solution.

Zinc-Promoted Barbier-Type Reaction of Propargyl Bromide with Aldehydes in Aqueous Media

Abstract In the prese of metallic zinc, propargyl bromide is found to react with aldehydes at room temperature in tetrahydrofurane-saturated aqueous ammonium chloride (5:2) to afford the corresponding homopropargylic alcohols in moderate to high yields together with small amounts of α-allenic alchohols.

3-Lithiopropyl tert-Butyl Thioether: A New γ-Functionalised Organolithium Compound ( d3-Reagent) in Synthetic Organic Chemistry

The reaction of 3-bromo or 3-chloropropyl tert-butyl thioether ( 1a or 1'a) with an excess of lithium powder and a catalytic amount of naphthalene (2,5 mol %) in THF at −78 °C followed by treatment with an electrophile (H 2O, D 2O, Me 2S2, CO 2) at the same temperature leads, after hydrolysis, to the expected products 2. Alternatively the process can be carried out under Barbier-type reaction conditions [lithiation in the presence of the electrophile: Me 3SiCl, Bu tCHO, PhCHO, Me 2CO, (CH 2) 4CO, (CH 2) 5CO, PhCOMe, c-C 3H 5COPh] and using DTBB as the arene catalyst at 0 °C. De- tert-butylation of products 2 with mercury(II) acetate and sulfhydric acid yields different sulfurated derivatives depending on the structure of the starting thioether.

Direct transformation of allylic and benzylic alcohols or their silylated derivatives into organolithium compounds

The reaction of allylic or benzylic alcohols 1 with n-butyllithium followed by treatment with lithium powder and a catalytic amount of DTBB (5 mol %) in THF at room temperature gives a solution of the corresponding alkyllithium reagent, which reacts in situ with different electrophiles to yield the expected products 2. Alternatively, the O-silylated derivatives of the same alcohols are lithiated under Barbier-type reaction conditions to afford the same reaction products with better yields.

A new procedure for the production of highly reactive metal powders by pulsed sonoelectrochemical reduction

Submicronic metal powders are produced by a new technique based on the combination of pulsed sonochemistry and electrochemistry. Particularly, zinc powder exhibits a high reactivity in Barbier type reaction in aqueous medium.

Highly efficient carbonyl allylation of 1,3-dicarbonyl compounds in aqueous medium

Beta-keto esters undergo efficient carbonyl allylation reactions in aqueous medium through a Barbier-type reaction. The reaction is general and a variety of 1,3-dicarbonyl compounds have been alkylated successfully using allyl bromide or allyl chloride in conjunction with either tin or indium.

Trimethylenemethane dianion equivalent in aqueous medium

Via an indium mediated Barbier-type reaction in aqueous medium, carbonyl compounds react with a trimethylenemethane dianion equivalent to give the corresponding diols.

Organolithium reagents by reductive decyanation of nitriles with lithium and a catalytic amount of 4,4′-Di- tert-butyl-biphenyl in a Barbier-Type reaction

The reaction of different nitriles 1 with an excess of lithium powder (1:14 molar ratio) and a catalytic amount of 4,4′-di- tert-butylbiphenyl (5 mol %) in the presence of a carbonyl compound (Barbier-type conditions) in THF at low temperature (−30 or −78°C) leads to the corresponding compounds 2 resulting from the coupling between the electrophile and the organolithium intermediate arising from a reductive decyanation of the starting nitrile 1. This new reaction can be also applied to the use of trimethylchlorosilane as electrophile at 0°C.

Reductive Cleavage of Allyllic Ketals by an Arene-Catalysed Lithiation: A Simple and Direct Route to Masked Lithium Homoenolates

The reaction of acrolein diethyl acetal 1 with an excess of lithium powder and a catalytic amount of 4,4′-di- tert-butylbiphenyl (DTBB; 2.5 mol %) in the presence of a carbonyl compound 2 in THF at 0°C leads, after hydrolysis with water, to the corresponding γ-coupling products 3 as a Z/E mixture, the Z-isomer being mainly the major one. When the final hydrolysis was carried out in acidic conditions (3 N hydrochloric acid) followed by treatment with silicon compounds of the type R 3SiNu in the presence of boron trifluoride etherate in dichloromethane at temperatures ranging between −78 and 20°C, the corresponding substituted tetrahydrofurans 4 were obtained. The same Barbier-type reaction applied to 2-cyclopentenone ethylene ketal 5 yields, after acid hydrolysis, the expected 3-substituted cyclopentanones 6. In all cases overall yields are moderates.

Barbier-type reaction of fluoroalkyl iodides with aldehydes without activation

Fluoroalkyl iodides react with aldehydes in the presence of zinc in N,N-dimethylacetamide without activation, giving a variety of fluoroalkylated carbinols in 72%–90% yield. The reaction provides a convenient method for the synthesis of these compounds.

Water-Promoted Organic Reactions

The reactions reviewed herein are those showing an unusual outcome when performed in water or in an aqueous medium. Notably, transformations are included for which the hydrophobic effect might be invoked as the activation factor, as well as cases where water leads to valuable changes compared to traditional solvents, except when they are clearly due to the polarity as for example in nucleophilic substitution reactions and except when the effect comes from the addition of a few equivalents of water. 1. Introduction 2. Physicochemical Background 2.1 Structure of Water 2.2 Aqueous Solutions of Simple Molecules 2.3 Hydrophobic Effects 2.4 Reactivity in Water 3. Pericyclic Reactions 3.1 Diels-Alder Reactions 3.2 Hetero Diels-Alder Reactions 3.3 Dipolar Cycloadditions 3.4 Claisen Rearrangements 4. Nucleophilic Additions 4.1 Aldolisation (Mukaiyama Reaction) 4.2 Michael-Type Reactions 4.3 Other Nucleophilic Additions 5. Organometallic Chemistry 5.1 Barbier-Type Reactions 5.2 Transition Metal Complex Catalyzed Reactions 5.3 Other Metal-Catalyzed Reactions 6. Oxidations 7. Reductions 8. Photochemistry 9. Conclusion