Tandem Reactions and Super Acids

Chemistry Level pending

You are tasked to synthesise the above compound's derivative.

You start with Succinaldehyde , Benzylamine and b-ketoglutaric acid whose formulae are \(C_{4}H_{6}O_{2}\) , \(C_{7}H_{9}N\) , \(C_{5}H_{6}O_{5}\) respectively.

These compounds undergo a tandem reaction to give precursor P. Now,

  • P is reduced with \(NaBH_{4}\) and then reacts with \(NaCN\) in presence of \(TsOH\) to give A
  • A reacts with DIBAL-H to form B after hydrolysis.
  • B reacts with 2-chloro ethanol in presence of piperidine and a catalytic amount of \({H}^{+}\) to give C after hydrolysis.
  • C is now oxidised in acidic \(KMnO_{4}\) to give D
  • D is decarboxylated to give precursor E whose formula is \(C_{16}H_{21}O_{2}N\)
  • E undergoes hydrogenation in presence of palladium to give the precursor F
  • F forms its silver salt and on reaction with \(Br_{2}\) gives G
  • G undergoes an intramolecular reaction to form the target molecule.

You call the target molecule X and carry out the next set of reactions on it:

  • X on hofmann exhaustive methylation gives an unstable compound Y
  • Y immediately rearranges in presence of \({H}^{+}\) and heat to give W
  • W on mono chlorination followed by reaction with \(AgF\) gives a compound T

T reacts with \(SbF_{5}\) to give a complex of antimony and a very stable cation V.

However V can be thought of as a tropylium cation derivative and it exceeds the tropylium carbocation's mass by b units.

In B let a denote the sum of double bonds between carbons and the number of oxygen atoms.

Calculate the value of b - a - 1


  • Problem 7 in 2016's IChO
  • Teleanu Florin's problem

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