5. The Robinson Annulation, named after an English chemist Sir Robert Robinson, is a beautiful reaction used to synthesi

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5 The Robinson Annulation Named After An English Chemist Sir Robert Robinson Is A Beautiful Reaction Used To Synthesi 1 (51.05 KiB) Viewed 7 times

5. The Robinson Annulation, named after an English chemist Sir Robert Robinson, is a beautiful reaction used to synthesize 6-membered rings. Its development was instrumental in the synthesis of polycyclic compounds such as steroids. The reaction works in two parts: (1) a conjugate (1.4)- addition to an unsaturated carbonyl by an enolate and (2) a subsequent Aldol condensation. An example of such a reaction is drawn below. HGC HyC mor + HC KOH EtOH 80 °C HC H3C (a) Draw the enolate that would act as the nucleophile in the conjugate [1,4]-addition: (b) Draw the product of the conjugate [1,4]-addition of the enolate from part (a): (c) Please provide the mechanism for the Aldol condensation showing how the product in step (b) arrives at the final product drawn above in the reaction scheme using proper arrow push notation. Show all arrows and intermediates, and don't forget formal charges.