Grignard Corey-Seebach Reactions Lab Report

Side reactions are reactions that compete with one another that produce unwanted products. One of the competing reactions with the Grignard reaction was the Grignard reagent reacting with oxygen to form peroxide which is very reactive. The second most electronegative element is oxygen. The second competing reaction was the Grignard reagent reacting with carbon dioxide to form a carboxylic acid. The carbon dioxide contains an electrophilic carbon. The products from these two side reactions that are problematic but are not important because there is a very finite amount of oxygen and carbon dioxide that is dissolved in the solvent. If performing the experiment without air completely, then oxygen and carbon dioxide would be eliminated. The third competing reaction is when the Grignard reagent reacts with a halide to form a C-C bond that is not needed.

Organometallic compounds, such as Grignard reagents, are molecules containing carbon-metal bonds and are often used to create new carbon-carbon bonds. Grignard reagents—or organomagnesims— are specifically those that have a carbon-magnesium bond.

Hydrogens, alkyls, or aryls bonded to carboxyl groups—made up of a carbonyl group and a hydroxyl group—are known as carboxylic acids. Derivatives of carboxylic acids include acid chlorides, esters, anhydrides, amides, and generally nitriles. These derivatives are formed by the replacement of the hydroxyl group with a different electronegative heteroatom substituent, which can be a single atom, such as a chlorine atom, or a group of atoms, such as in the formation of

A reaction of the Grignard reagent and carbon dioxide results in an acid, and reaction of a nitrile and a Grignard reagent produce a carbonyl via an imine intermediate. These are show below, respectively.

This allows for the extension of the molecule with more carbons or even carbon molecules. In the lab bromobenzene was reacted with magnesium to form a Grignard reagent. This reagent formed was reacted with butanal an aldehyde containing four carbons to form 1-phenyl-1-butanol. 1-phenyl-1-butanol is a molecule containing a benzene ring with an alcohol and a four carbon chain in the same location. When the Grignard reagent reacts, the negatively charged carbon on the benzene ring attacks the partially positively charged carbon containing the doubly charged oxygen.

The Grignard reaction is an important synthetic process by which a new carbon to carbon bond is formed. Magnesium metal is first reacted with an organic halide forming the Grignard reagent. The Grignard reaction is the addition of an organomagnesium halide (Grignard reagent) to a ketone or aldehyde, to form a tertiary or secondary alcohol, respectively. For example, the reaction with formaldehyde leads to a primary alcohol. Grignard Reagents are also used in the following important reactions: The addition of an excess of a Grignard reagent to an ester or lactone gives a tertiary alcohol in which two alkyl groups are the same, and the addition of a

Through the use of the Grignard reaction, a carbon-carbon bond was formed, thereby resulting in the formation of triphenylmethanol from phenyl magnesium bromide and benzophenone. A recrystallization was performed to purify the Grignard product by dissolving the product in methanol. From here, a melting point range of 147.0 °C to 150.8 °C was obtained. The purified product yielded an IR spectrum with major peaks of 3471.82 cm-1, 3060.90 cm-1, 1597.38 cm-1, and 1489.64 cm-1, which helped to testify whether the identity of the product matched the expected triphenylmethanol. The identity of the product being correct was further confirmed by way of both proton and carbon-13 NMR spectra. This is due to the fact

The purpose of this lab is to generate an organometallic reagent in solution by reducing a ketone starting material to a tertiary alcohol using phenylmagnesium bromide. This will be accomplished by utilizing a Grignard reagent. Grignard reagents are highly polarized compounds that result in being a strong nucleophile and a strongly basic reagent. Because of this, they are highly sensitive to protic solvents. In order to not have the Grignard react with the protic solvetns, diethyl either will be used as an aprotic solvent. The product of this expirment will not be a reacmic mixture because of the symmetrical nature of the alcohol product, triphenylmethanol.

In this experiment, a nucleophilic substitution was performed, where a chloride nucleophile substituted a tertiary hydroxyl group on 2-methyl-2-butanol. In a nucleophilic substitution reaction, an electron rich nucleophile attacks a positively or partially positively charged electrophile, and replaces a leaving group. In this reaction, chloride ions are the nucleophile, the tertiary carbon in 2-methyl-2-butanol is the electrophile, and water is the leaving group. In the mechanism for this reaction, the oxygen from the hydroxyl group of the 2-methyl-2-butanol attacks the hydrogen of the HCl, causing heterolytic cleavage of the HCl, resulting in a chloride ion, and in the oxygen bonding to an extra hydrogen, and becoming positively charged.

In the first step of azo coupling the diazonium intermediate is synthesized. This process is called diazonation, in which the diazonium intermediate is formed by the reaction between sulfanilic acid (an aromatic amine)

The oxidation reaction occurs as a two-step reaction. The first step involves the formation of chromate esters and the second step is an elimination reaction that will produce the carbonyl group necessary to make either a ketone or an aldehydes. The reaction is hallmarked by the breaking of a C-H bond and the formation of a C-O bond (James, 2014). Specifically when oxidizing alcohols, it is important to note that primary alcohols can be converted to aldehydes as well as completely to carboxylic acids, secondary alcohols are converted to ketones and no further, and tertiary alcohols cannot be oxidized. The oxidizing agent removes the hydrogen from the –OH group and the hydrogen from the C-H group attached to the –OH group in a compound. Tertiary alcohols cannot be oxidized because they lack the C-H bond that is present in both the oxidation of primary and secondary alcohols (Clark, 2003).

This lab consisted of the conversion of alcohols into alkyl halides through common substitution methods. These methods include SN1 and SN2 mechanism, both of which can occur for this type of reaction. For both reactions, the first step of protonation will be to add hydrogen to the –OH group and then the rest of the reaction will proceed according to the type of mechanism. SN1 reactions form a cation intermediate once the H2O group leaves, then allowing a halide (such as Br) to attack the positively charged reagent1. On the other hand, SN2 reactions are one-step mechanism in which no intermediate is formed and the halide attaches as the leaving

The objective of this experiment is to synthesize triphenylmethanol using a Grignard reagent. A Grignard reagent is a carbon-magnesium halide, where the carbon acts as a nucleophile. As shown in Mechanism 1, it is formed by reacting an alkyl halide, in this case a bromide (bromobenzene), with magnesium metal in anhydrous ether. During the preparation of the Grignard reaction, another by-product, biphenyl, will be formed; this is caused from the rapid addition of bromobenzene to the Grignard reagent solution. However, the by-product will later be removed with petroleum ether. It is also important to have no traces of water as the Grignard reagent is very reactive with water. A reaction between the Grignard reagent and water will result in an

Although the original function of HbHNL is to produce HCN from acetone cyanohydrins for plant defense purpose, its reversible reaction to produce enantiopure cyanohydrins makes it an industrial relevant enzyme (Fig. 1.6a). Besides acetone, it is also able to take a bigger substrate such as benzaldehyde and turn it into mandelonitrile with optical purity up to 99%.15 HbHNL is known to turn different aliphatic or aromatic aldehydes and methyl ketones into different cyanohydrins.15 Cyanohydrins are useful precursors to agrochemicals and pharmaceutical products. For example, (R)-2-chlorobenzaldehyde cyanohydrin is the precursor of Clopidogel (Plavix), which is a blood clot inhibitor.16 Pyrethroids, made from (S)-phenoxybenzaldehyde cyanohydrins, are an important synthesis route to insecticides.16

The M-C3 and C1- C2 single bonds are broken to form a metal alkylidene and ethylene.