Compound A reacts with 1 molar equivalent(s) of hydrogen upon catalytic hydrogenation. A undergoes reaction with ozone, followed by Zn treatment, to give: Propose a structure for A.

Both pyrrole and pyridine are nitrogen containing heterocycles that are 6π Hückel aromatic. Describe the aromaticity and observed basicity for that molecule, which is more basic, explain and show the acid -base reaction involved.

Answer ALL parts. (a) Treatment of enone C with tetrabutylammonium fluoride leads to the formation of heterocycle D. 2 steps BU4NF C9H1602 A + B D OSIME,tBu (i) Enone C can be prepared from alkyne A and aldehyde B in two steps via a gold-catalysed reaction. Identify A and B and provide reagents/conditions for a synthesis of C. (ii) Give the structure of D and classify the ring-closing reaction for its formation from C according to Baldwin's rules (iii) Sketch the key molecular orbitals involved in the ring-closing reaction in part (ii) and hence explain whether the reaction is favourable or unfavourable.

Give detailed Solution with explanation