CHEM 343 Lecture Notes - Protecting Group, Aldehyde, Ketone

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lemondog142

10 Jun 2014

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Document Summary

Reductive amination the reaction of an aldehyde or a ketone with ammonia (or with an amine) in the presence of a reducing agent. Hydrate a molecule with two oh groups on the same carbon (gem-diols) The extent to which an aldehyde or a ketone is hydrated in an aqueous solution depends on the aldehyde or ketone. Hemiacetal (hemiketal) the product of the addition of one equivalent of an alcohol to an aldehyde (ketone) Acetal (ketal) the product formed when a second equivalent of an alcohol is added. Acetal (or ketal) formation requires an acid catalyst. Protects a functional group from a synthetic operation that it would otherwise not survive. The c-s bond of thioacetal (or thioketal) can be converted into c-h bonds using h2 and. The wittig reaction a reaction in which an aldehyde or ketone reacts with a phosphonium ylide to form an alkene. Ylide a compound that has opposite charges on adjacent, covalently bonded atoms with complete octets.

Related Questions

Since electron density associated with the carbon atom in a carbonyl group is drawn towards the oxygen atom, this carbon is susceptible to reaction by a _______________. When the carbonyl group is associated with an aldehyde and the _______________ is an alcohol, the resultant reaction results in production of a(n) _________________ . In the presence of excess alcohol relative to aldehyde, this same carbon can react twice with the alcohol molecule to generate a(n) _______________________ .

An acetal forms when two alcohol molecules react with an aldehyde or a ketone. The process involves the addition of two âOR groups from the alcohol to the carbonyl group, and the elimination of a water molecule. R represents the hydrocarbon chain of the alcohol. The general reaction and structure for an acetal are shown here.

Part A: Draw the acetal produced when ethanol adds to ethanal.

Part B: Draw the acetal produced when ethanol adds to propanone.