Nucleophilic Addition Reaction Mechanism, Grignard Reagent, NaBH4, LiAlH4, Imine, Enamine, Reduction

This paragraph introduces nucleophilic addition reactions, focusing on the mechanism involving a carbonyl group, typically found in ketones. It explains how a nucleophile, attracted to the partially positive carbon of the carbonyl group, attacks and forms a tetrahedral intermediate. The reaction concludes with the oxygen atom grabbing a hydrogen from an acid, resulting in an alcohol. The paragraph then sets up an example using cyclopentanol and methyl magnesium bromide, prompting viewers to predict the product and propose a mechanism.

The paragraph delves into the specifics of converting aldehydes and ketones into alcohols through nucleophilic addition reactions. It describes the use of Grignard reagents, such as methyl magnesium bromide, to add a methyl group across the carbonyl group, forming a secondary alcohol. The mechanism is explained in two steps: nucleophilic attack and protonation. It also discusses alternative methods like using sodium borohydride for reduction, and the outcomes of applying lithium aluminum hydride to esters and acid chlorides, resulting in different types of alcohols.

This section discusses the reduction of esters to alcohols using methyl magnesium bromide and the reaction of acid chlorides with sodium borohydride. It explains that esters can be reduced to aldehydes by adding two R groups, while acid chlorides are more reactive and can be reduced to primary alcohols. The mechanism involves nucleophilic attack, tetrahedral intermediate formation, and subsequent steps leading to the final alcohol product. It also touches on using DIBAL (diisobutyl aluminum hydride) for selective reduction to aldehydes.

The paragraph explores the reactions involving cyclic esters, known as lactones, with sodium borohydride, which opens the ring and results in a diol. It contrasts this with the reaction of a lactone with methyl magnesium bromide, leading to a ketone and then a tertiary alcohol. The mechanisms are described step by step, highlighting the nucleophilic attack, ring opening, and the formation of alcohol groups.

This section covers the reaction of phenol magnesium bromide with carbon dioxide to form benzoate, and the subsequent conversion to benzoic acid with the addition of H3O+. It also discusses the reaction of phenol magnesium bromide with epoxides to add two carbon atoms to the benzene ring, forming a primary alcohol upon acidification. The mechanisms are outlined, including the initial nucleophilic attack and the final steps to form the products.

The paragraph explains the difference between conjugate addition and direct addition in reactions with nucleophiles. It uses the example of an alpha-beta unsaturated ketone reacting with a Grignard reagent and cyanide. The mechanisms for both reactions are described, showing how the Grignard reagent adds directly to the carbonyl carbon, while cyanide adds to the beta carbon, leading to different products.

This section discusses the reactions of ketones with primary and secondary amines under mildly acidic conditions. It explains the formation of imine when a primary amine reacts with a ketone and the formation of enamine with a secondary amine. The mechanisms for both reactions are detailed, including the initial nucleophilic attack, protonation steps, and the final formation of the products.

The paragraph introduces reductive amination, a process where a ketone is first converted to an amine and then selectively reduced to an amine using sodium cyanoborohydride. It contrasts this with the use of sodium borohydride, which could lead to a mixture of products. The mechanism for the reduction of an imine to an amine is described, including the formation of intermediates and the final steps to isolate the amine product.