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Neighbouring group participation

27 questions on Neighbouring group participation from the Organic Reaction Mechanisms III: Nucleophilic Substitution chapter: 4 NEET level, 11 JEE Main, 12 JEE Advanced. Each one opens with its answer and solution.

Practice this topic All Organic Reaction Mechanisms III: Nucleophilic Substitution topics

The term 'anchimeric assistance' means NEET level
In neighbouring group participation, the nucleophile attacks the carbon twice in succession, each time from the side opposite to the group being displaced. The ... NEET level
Hydrolysis of Y-CH2CH2-Cl in water is fastest for which Y? NEET level
Sulfur mustard, ClCH2CH2-S-CH2CH2Cl, is hydrolysed rapidly in water through a reactive three-membered cyclic intermediate. This intermediate is a(n) NEET level
Optically pure (S)-2-bromopropanoate ion, CH3-CH(Br)-COO-, is left in water with a low concentration of hydroxide (so that the external nucleophile is poorly av... JEE Main level
Each of the two isomers trans-2-chlorocyclohexan-1-ol and cis-2-chlorocyclohexan-1-ol is treated with aqueous NaOH. Which statement is correct? JEE Main level
2-Chloroethyl ethyl sulfide, CH3CH2-S-CH2CH2-Cl, hydrolyses in water much faster than a typical primary chloride such as 1-chlorobutane, and the rate is indepen... JEE Main level
(CH3)2N-CH2CH2-Cl is dissolved in water. The reactive intermediate that is formed by loss of chloride and that is then opened by water is JEE Main level
2-Phenylethyl tosylate in which the carbon bearing OTs is labelled with ^13C, i.e. C6H5-CH2-^13CH2-OTs, is solvolysed in acetic acid. Assume that all of the pro... JEE Main level
trans-2-Acetoxycyclohexyl tosylate solvolyses in acetic acid about a thousand times faster than the cis isomer. The best explanation is that in the trans isomer JEE Main level
Assertion (A): cis-2-Acetoxycyclohexyl tosylate solvolyses much more slowly than the trans isomer. Reason (R): In the cis isomer the acetoxy group cannot reach ... JEE Main level
Match the neighbouring group in List I with the cyclic intermediate in List II. List I: P the carboxylate group of 2-bromopropanoate; Q the sulfide sulfur of CH... JEE Main level
Select the correct statement(s) about neighbouring group participation (NGP) in nucleophilic substitution. JEE Main level
Which of the following chlorides is expected to hydrolyse in water mainly by anchimeric assistance rather than by an ordinary SN2 attack of solvent? JEE Main level
(R)-1-Chloropropan-2-ol, CH3-CH(OH)-CH2Cl, is treated with one equivalent of NaOH to give 2-methyloxirane (propylene oxide) by an intramolecular SN2 ring closur... JEE Main level
(2S,3R)-3-Bromobutan-2-ol is warmed with concentrated HBr. The OH group is lost (as water) with anchimeric assistance by the neighbouring bromine, giving a brid... JEE Advanced level
(2S,3S)-3-Phenylbutan-2-yl tosylate is solvolysed in acetic acid. Assume that the reaction goes exclusively through phenyl participation (a bridged phenonium io... JEE Advanced level
A single enantiomer of trans-2-acetoxycyclohexyl tosylate is heated with potassium acetate in acetic acid. The reaction proceeds by participation of the neighbo... JEE Advanced level
A single enantiomer of trans-1-chloro-2-(methylsulfanyl)cyclohexane is stirred in aqueous sodium hydrogen carbonate. The C-Cl bond is lost with anchimeric assis... JEE Advanced level
(S)-Alanine, CH3-CH(NH2)-COOH, is treated with NaNO2 in dilute sulfuric acid to give the diazonium ion, CH3-CH(N2+)-COOH, which then reacts with water. The pred... JEE Advanced level
The anions Br-(CH2)_n-COO- cyclise to lactones by intramolecular SN2 attack of the carboxylate oxygen on the C-Br carbon. Under identical conditions in water, w... JEE Advanced level
Sulfur mustard, ClCH2CH2-S-CH2CH2Cl, is hydrolysed in water. Select the correct statement(s). JEE Advanced level
Optically pure (S)-2-bromopropanoate ion is hydrolysed in aqueous NaOH. Select the correct statement(s). JEE Advanced level
trans-2-Acetoxycyclohexyl tosylate and cis-2-acetoxycyclohexyl tosylate solvolyse in acetic acid at very different rates. Select the correct statement(s). JEE Advanced level
Which of the following compounds will give a three-membered cyclic ether (epoxide) when treated with aqueous NaOH, by intramolecular SN2 ring closure of the alk... JEE Advanced level
3-Phenylbutan-2-yl tosylates and related phenyl-bearing substrates solvolyse with participation of the phenyl ring. Select the correct statement(s). JEE Advanced level
Select the correct statement(s) about neighbouring halogen participation (halonium ions). JEE Advanced level