a) Comment on the selectivity observed in step (vi) (the reaction of 3 with LiN3). What type(s) of selectivity is/are observed? How/why does it arise? )

 

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CH,OH но но но но Pb(OAc)e v. HCIu CO,Et -OH OH OH CH,OH v. 2 TBSO TBSO vi-ix TBSO yi. LIN, THE then H0 TBS = tert-butyldimethylsilyl (-Si((CHahC(CHa)) Ac = acetyl (-COCH,) CH,OH но но но но Pb(OAc)e v. HCIu CO,Et -OH OH OH CH,OH v. 2 TBSO TBSO vi-ix TBSO yi. LIN, THE then H0 TBS = tert-butyldimethylsilyl (-Si((CHahC(CHa)) Ac = acetyl (-COCH,)