Phosphorus Ylide Formal Lab Report

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Draw the structure of the organic product for the reaction between the following compound and the phosphorus ylide shown. Solution The phosphorus ylide will only react with the carbonyl group. Final product  Comment: Think of the Wittig reaction as the reverse of oxidative cleavage of alkenes. Baeyer-Viliger Oxidation The Baeyer-Viliger oxidation is an organic reaction used to convert a ketone to an ester using a peroxyacid, with an “insertion” of one oxygen atom. • A peroxyacid can be prepared by reacting a carboxylic acid and hydrogen peroxide. RCOOH + H2O2  RCO3H + H2O • Peroxyacids serve as the oxidizing agent in the Baeyer-Viliger reaction. • For asymmetrical …show more content…

Carboxylic acids are stronger acids than peroxyacids. The negative charge on the oxygen atom of the carboxylate ion is extensively delocalized between two highly electronegative oxygen atoms; thus the conjugate base is resonance stabilized. Furthermore, the presence of two highly electronegative oxygen atoms will also exert a strong electron withdrawing inductive effect, leading to a more effective dispersal of the negative charge on the oxygen atom of the carboxylate ion. The negative charge on the conjugate base of the peroxyacid is not resonance stabilized. However, the presence of three highly electronegative oxygen atoms does exert a strong electron withdrawing inductive effect on the negative charge on the oxygen atom of the conjugate base. Nevertheless, the extent of negative charge dispersal is more effective for the carboxylate ion than for the conjugate base of a peroxyacid. Example 1 The acid dissociation constants, Ka, of four compounds are shown as follows. Explain the decreasing trend in acid strength of the four compounds. compound Ka/ mol dm-3 2-hydroxybenzoic acid 1.1 x …show more content…

N.B.: R refers to an electron-donating alkyl group. Aliphatic amines are more basic than phenylamines and phenylamines are more basic than amides. For aliphatic amines, the more R groups present, the stronger is the electron donating inductive effect. Thus, a tertiary amine is expected to be the most basic among the aliphatic amines. However, it isn’t. A tertiary amine is less basic than a secondary amine despite the former having three electron donating alkyl groups as compared to the latter’s two. This is because although the electron donating inductive effect is greater for the tertiary amine, the presence of three ‘bulky’ alkyl groups hinders its ability to donate its lone pair of electrons. For this particular example, the steric factor is more dominant than the electronic factor. For phenylamine, the lone pair of electrons on the N atom is delocalised in the benzene ring and hence renders them less available for coordination with a proton. For amides, the lone pair of electrons on the N atom is delocalized into the adjacent carbonyl group with a highly electronegative oxygen atom. Hence, amides are considered to be

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