Lego blocks

Chemistry Level 4

Growing up, I never believed in the Lego motto, "Half the fun is in building it yourself". A self assembling Lego Kit was what I really wanted, but with CES 2017 ending and no word from Lego it might remain a dream.

If you think of Lego blocks as atoms, self assembly is a dream that has been realised. The following scheme related to the synthesis of Alistonitrine A illustrates this:

We start with the above compound,

  • We add \(\ce{NaBH_4}\) and tert-Butyldimethylsilyl chloride in presence of imidazole . We then heat it in presence of silica gel to obtain A. It possesses \(\ce{C_{39}H_{63}O_{9}N_{3}Si}\) as its molecular formula.
  • A reacts with Lithium bis(trimethylsilyl)amide and Iodine gas while slowly being heated to room temperature to give B.
  • B is hydrolysed in aqueous \(\ce{KCN}\) and later heated in \(DMF\) to give C whose molecular formula is \(\ce{C_{37}H_{61}O_{7}N_{3}Si}\).
  • C reacts with Tetra-n-butylammonium fluoride and later with Pyridinium chlorochromate to form compound D.
  • D reacts with \(\ce{PCl_{5}}\) to generate E.
  • E with Trimethylsilyl trifluoromethanesulfonate and 2,6-lutidine to generate a intermediate X. In presence of \(\ce{K_{2}CO_{3}}\), X reacts to form F
  • F reacts with \(\ce{NaOCl}\) in presence of a catalyst to generate the required compound.

Let \(\alpha\) denote the number of rings in compound A and \(\beta\) denote the number of rings in B.

Find the value of \(\alpha - \beta\).


If the catalyst used in the final step has the following structure:

What type of symmetry elements does it possess?


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