i) Suggest reagents that would achieve steps (ii) and (iii) and explain the order in which you choose to perform these steps. (3 marks)

ii) Consider step (v) of the synthesis. Briefly explain the two transformations that occur in this step, then give two reasons for the choice of a benzyl ether to protect the alcohol of starting material 17. (3 marks)

 

Transcribed Image Text:

OH @ a) n-Buli OTBDMS отвомS Bno 16 b) O. 17 OBn OMOM NBoc он омом Bno NHBoc 18 Bno 19 (V) Ha Pa(OH),/C, THE OMOM NBoc OMOM M) HO но 15 20 TBDMS terfbutyidimethylsly MOM methaxymethyl Bn benzyl Boc terfbutoxycarbonyl OH @ a) n-Buli OTBDMS отвомS Bno 16 b) O. 17 OBn OMOM NBoc он омом Bno NHBoc 18 Bno 19 (V) Ha Pa(OH),/C, THE OMOM NBoc OMOM M) HO но 15 20 TBDMS terfbutyidimethylsly MOM methaxymethyl Bn benzyl Boc terfbutoxycarbonyl