Question

(a) Draw a stepwise, detailed mechanism for the following reaction. Used curved arrows to show the movement of electrons. Br CN NaCN DMF NaBr (b) Assign the configuration (Ror S) of the chiral centre in the substrate and product (c) List the bonds broken and formed in this reaction (d) Assume that this is an endothermic reaction. Draw an energy diagram for this reaction. Label the axes, reactants, products, E, and AH. Draw the structure for both transition states.

Answer 1

CN No CN it Nalor DME Mechanism Br CN H Br 2 TOS Non This rexu passes through son mechanisma cÑ attacks from the backside of Bratom. b) Zubstrate priority >c>d sequence product d Bor 71 11 eNew) cs CE) rotation along abe is clockwise but it present in outside of the plane so configuration is just reverse. because rotation along abe clockwise

c) Here (o sr bond is broken & c-en bond is formed. then As per the question reaction is endothermic, That means product has higher energy reactant. So the energy profile diagram should be like Tas E 1 Alt product reactant Doch AHE H product - Hreactant = tve have to Here only one transition state possible But you. think there are toro T.S, you take first one in which C-CN bond length> (-Br bond length & for the 2nd T's (-for bond length > c- en bond length

That should be like EN Br Poflowering Tos I 1:51 And now the energy profile diagram should be TS 1 T'S1 4 prochet TAH E reactant