# 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 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 $$\alpha - \beta$$.

Bonus:

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

What type of symmetry elements does it possess?

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