Acetyl chloride [1] is treated with diazomethane [2] yielding the diazonium salt [3] . The chloride [4] produced reacts with the diazonium salt to give the α-chloroketone [5] .

The Abuzov reaction is used in the synthesis of phosphonates [3] from phosphites [1] .

Arbuzov's reaction The phosphonates obtained in the Abuzov synthesis are used as starting materials in the Horner-Wittig synthesis.

Acetylacetic synthesis allows ketones to be prepared by C-alkylation of ethyl acetylacetate (ethyl 3-oxobutanoate). Ethyl acetoacetate can be deprotonated at the C2 or C4 positions depending on the type and amounts of base used. The hydrogens at the C2 position they present significant acidity (pKa=11) due to stabilization of the conjugate base on the two neighboring carbonyls.In the presence of a base equivalent (alkoxides, LDA, NaHMDS, etc.) a ketoester enolate capable of attacking numerous carbonated electrophiles.

 acetylacetic synthesis 01

Sigmatropic [3,3] rearrangements of N-allyleneamines are known as aza-Claisen rearrangements. This reaction is analogous to the Claisen rearrangement of allyl vinyl ethers.

aza claisen 01

Acyloin condensation transforms esters [1] into alpha-hydroxyketones [2]. This reaction is carried out with sodium metal in an inert solvent.

acyloinic condensation

1,5-Dienes isomerize by sigmatropic-[3,3] rearrangements on heating. Reaction known as Cope rearrangement. The rearrangement of N-substituted 1,5-dienes is called an aza-Cope rearrangement. Depending on the position occupied by nitrogen we have: 1-aza-, 2-aza-, 3-aza-Cope. The 3-aza-Cope regrouping coincides with the aza-Claisen.

aza cope 01

Aldol condensation is a reaction of aldehydes or ketones [1] that forms 3-hydroxycarbonyls (aldols) [2] . 3-Hydroxyaldehyde [2] under dehydration conditions by heating yields an alpha, beta-unsaturated aldehyde [3] .
aldol condensation

Reaction analogous to the Wittig rearrangement, in which alpha metal ethers rearrange alkoxides, generating secondary or tertiary alcohols after hydrolysis. In the case of aza-[2,3]-Wittig, these are alpha metallated allylic tertiary amines which produce secondary amines after hydrolysis.

aza23wittig 01

Acids and bases catalyze the isomerization of N-glycosides (glycosamines) from aldoses to 1-aminodeoxyketoses. This rearrangement can be catalyzed with a number of Lewis acids (CuCl 2 , MgCl 2 , AlCl 3 , SnCl 4 ). The amine used as a reagent can be primary or secondary, aliphatic or aromatic.

amadori reaction 01

The Baeyer Villiger oxidation allows the transformation of ketones into esters.