Organic reaction mechanisms: involving addition, elimination and substitution reactions with electrophilic, nucleophilic or radical species. Determination of reaction pathways.
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1.The intermediate A and the major product B in the following reaction sequence are
In first step opening of epoxide takes place in SN2-manner. In second step the phosphrousylide formed are unstabilised which give z-alkene.
2.The mechanism and the product formed in the following reaction, respectively, are
Since Alkyl halide is tertiary in nature hence only possibility of SN1 mechanism.
Moreover, SN1there is formation of carbocation hence racemization take place hence stereochemistry is not defined.
(Reference : Organic Chemistry , clayden)
3.The major product formed in the following reaction is…..
4.The major products A and B in the following reactions are
Heating dimethylmenthyl amine oxide gave a mixture of 2- and 3–menthene, whereas isomeric neo menthylamine oxide gave only 2–menthene. This is an example of pyrolytic syn elimination
5.The correct combination of the following reactions and their ρvalues is
|B||ArO–+EtI in EtOH||Q||– 0.99|
|C||ArCO2+ aq NaOH in EtOH||R||– 2.69|
(a) A-P; B-R; C-P
(b) A-R; B-Q; C-P
(c) A-R; B-P; C-Q
(d) A-Q; B-R; C-S
𝜌 is a reaction constant. Positive value of 𝜌 indicates more electron in the transition state and negative sign indicates less electron in transition state.
Any reaction that involves the nucleophilic attack on carbonyl group as rate determining step will have 𝜌 = 2- 3, hence only option (1) is correct
6.The major product formed in the following reaction is
In the presence of acid, protonation takes place, thus reaction will proceed via SN1 mechanism.
Thus, retenation of configuration will be observed and hence the product formed will be