Addition reactions of aldehydes

Nucleophilic Addition Reactions of Aldehydes and Ketones (Chapter 19)... 

Nucleophilic addition reactions of aldehydes and ketones (a) Addition of hydride alcohols (Section 19.7)... 

CEJ1358> and the ruthenium mediated isomerization of double bonds (cf. Scheme 89, Section 8.11.7) <2007TL137> are recent examples of transition metal catalyzed manipulations at the side chain carbon atoms of 1,3-heterocycles. A novel side-chain addition reaction of aldehydes to 6-alkylidene-l,3-dioxin-4-ones was used for the construction of intermediates of lophotoxin <2006CJC1226>. An acid-catalyzed intramolecular cycloaddition of a hydroxy group to an alkene has been effected by the presence of an adjacent 1,3-dithiane moiety <2006TL4549>. 

A summary of nucleophilic addition reactions of aldehydes and ketones. 

These compounds are unique alkylating or arylating reagents and their reactivity has been reviewed [25,26], Some chemoselective reactions are presented. The addition reaction of aldehydes to 10 proceeds faster than that of ketones [23,25,27,28], Compound 8 reacts chemoselectively with an acetal, and not with an ester group [29], The structure of TiMeCl3(dmpe) (12) has been determined both by X-ray and neutron diffraction analysis. The latter confirms that there is a unique agostic interaction of the a-hydrogen atom with the titanium atom [30,31], This weak interaction stabi-... 

Nucleophilic addition is the characteristic mechanism for addition reactions of aldehydes and ketones. It can be base-initiated in which a negative or neutral nucleophile attacks the carbonyl carbon generating a negative carbonyl oxygen that is subsequently neutralized. In the acid-initiated mechanism, hydrogen ion bonds to the carbonyl oxygen a carbocation results which is neutralized by the nucleophile. 

Other addition reactions of aldehydes oeeur. Water, for example, adds to the earbonyl of trichloroacetaldehyde to form chloral hydrate, a strong hypnotic and sedative known as knock-out drops or (when mixed with alcohol) a Mickey Finn. Complete the reaction by drawing the structural formula of chloral hydrate ... 

Scheme 13.14 Asymmetric Michael addition reactions of aldehydes with nitroalk-enes catalysed by peptides 18-21.

Radical Chain Addition Reactions of Aldehydes With Perfluoro Ketones and Chloro Perfluoro Ketones," J. Org. Chem., 347 (1967). 

The nucleophilic addition reactions of aldehydes and ketones occurring at the carbonyl carbon atom that we have studied so far are summarized below. In Chapters 18 and 19 we shall see other examples. 

Other reactions of carbohydrates include those of alcohols, carboxylic acids, and their derivatives. Alkylation of carbohydrate hydroxyl groups leads to ethers. Acylation of their hydroxyl groups produces esters. Alkylation and acylation reactions are sometimes used to protect carbohydrate hydroxyl groups from reaction while a transformation occurs elsewhere. Hydrolysis reactions are involved in converting ester and lactone derivatives of carbohydrates back to their polyhydroxy form. Enolization of aldehydes and ketones leads to epimerization and interconversion of aldoses and ketoses. Addition reactions of aldehydes and ketones are useful, too, such as the addition of ammonia derivatives in osazone formation, and of cyanide in the Kiliani-Fischer synthesis. Hydrolysis of nitriles from the Kiliani-Fischer synthesis leads to carboxylic acids. 

You should also read the sections in your lecture textbook that deal with the formation of esters and nucleophilic addition reactions of aldehydes. 

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