Question

1. (25 pts) Each of the following reaction sequences has one issue that would prevent the products from forming as shown. Identify the issue and briefly explain how the conditions could be changed to allow each reaction to form the products shown Core HNO3 H2SO NO2 LIAIH b Me (NH CI) EtO Me HO OH OH MeLi THF, -78 °C OH Br2 KOr-Bu Me d. MeO MeO t HOr-Bu A NBS Na (s) m-CPBA Me Me- Me 'Me HH NH3 ()

Answer 1

HNO3 -No₂ 2 (h soy In this esxn the presence of acid may cause the intramolecular ering formation. L'Al May Eto ome Nhyce no In this er on the wally is a strong hydride based reducing agent, along with ester, it will redrce the ketone too. To avoid this problem, first keto group is needed to be protected. It can be follow by - me OH OH O eto Тѕои о- - the WAlly HO Но,н® no me met B91 OM THF-76 n on on this reaction, meu ewed act as a very strong base. It is used here for metal halogen exchange uxn but it is highly basic in native, so it dep may deprotonate the hydroxyl group also so in order to proceed the reaction. "hydroxy group should be protected non me -si me

17 on O w I Me Buin on . Вя. K-tBy meo. S I nou meo HOLBY on this with the presence of Br, react with alkene and form brominium ion which is folloriced by ring opening by Bre but do not leads to the formation of desired product So choice of reagent is wrong. Here We use NBS with cell, which cause allylic Bromination and we get the product we want. Inventot preo & Ko te meo ее me NBS B1 a me - me Na MCPBA me NH,00°C NH, 1 fu uy on this reactim MUBA form alkenes. In second step, the presence of the epoxide ring at both