What does the Weinreb amide do?
The main synthetic use of Weinreb amides derives from their reactivity toward nucleophiles. They can be useful for the addition of Grignard or alkyllithium reagents to produce ketones. Other advantages are seen in the selective reduction of the Weinreb amides to the corresponding aldehydes.
How to make Weinreb amides?
Weinreb amides could be synthesized through a mild Pd-catalyzed cross-coupling of 3-thienyl-, or 3-benzo[b]thienylboronic acid with N-methoxy-N-methylcarbamoyl chloride (Eqns 53 and 54) (2010JOC1251).
Does Grignard react with amide?
The acidity of carboxylic acids and 1º & 2º-amides acts to convert Grignard and alkyl lithium reagents to hydrocarbons (see equations), so these functional groups should be avoided when these reagents are used.
Do Grignard reagents react with esters?
An ester (or an acid halide or an anhydride) reacts first with a Grignard reagent to form a ketone, which reacts further to give an alcohol. It is not usually possible to make and isolate a ketone through reaction of an ester or other acid derivative with only one mole of Grignard reagent.
How do aldehydes reduce amide?
N,N-disubstituted amides can be reduced to aldehydes by using an excess of the amide: R(CO)NRR’ + LiAlH4 → RCHO + HNRR’ With further reduction the alcohol is obtained. Some amides can be reduced to aldehydes in the Sonn-Müller method.
What does CuLi do in organic chemistry?
Gilman reagents, or Lithium organocuprates (R2CuLi), are useful nucleophiles in organic synthesis. These have a different reactivity from Grignard reagents and organolithiums, since Gilman reagents are softer.
Is Grignard a reagent?
Grignard reagents are formed by the reaction of magnesium metal with alkyl or alkyl halides. They are wonderful nucleophiles, reacting with electrophiles such as carbonyl compounds (aldehydes, ketones, esters, carbon dioxide, etc.) and epoxides.
Do amides react with ketones?
The most important use of ylides in synthesis comes from their reactions with aldehydes and ketones, which are initiated in every case by a covalent bonding of the nucleophilic alpha-carbon to the electrophilic carbonyl carbon.
Do Grignard reagents react with aldehydes?
Organolithium or Grignard reagents react with the carbonyl group, C=O, in aldehydes or ketones to give alcohols. The substituents on the carbonyl dictate the nature of the product alcohol. Addition to other aldehydes gives secondary alcohols. Addition to ketones gives tertiary alcohols.