Question

2. Predict the reagent(s) corresponding to each letter. Show stereochemistry where necessary. (2 marks each) (a) Н CN Он NH2 (b) Он CH3 к (c) ..ОBп OBn .OBn OBn м но O, но 1. R 2. S 1. P H3C,,, OH НаС».о, т 2. Q .OBn OBn

Answer 1

OH EI3N, DCM TSCI OM EL OTs NaCN, DMF as a D Den BV NaH, THE CI NiC12H2O NaBH4, MeOH NH2 CH3MgBr, noTHÉ OH H*, heat -CH₃ Simmon smith reaction 3) B .O.OBNOSO. THE NaOCH, ...OBnMeOH ...OBN Br Br OBn HOOH H* Og, Zn/H, OBn CS2. Mel THE HO OBn OH H, Paic, ",79) OB "MeOH " NaBH, MOH 07 ...OBn MeOH - o nSnBuZH, AIBN

(4-chlorophenyl)methanol react with Et3N and DCM with TsCl to form tosylate which was reacted with NaCN to form cyano derivative. Further, Cyano derivative reacts with 1,3-dibromo propane to form four membered cyclized product which was further reduced by NiCl2.6H2O and NaBH4 to form amine.

2) cyclopentanone react with methyl magnesium bromide to form tertiary alcohol which undergo dehydration to form alkene. Finally, simmon smith reaction to form cyclopropane ring.

3) (2S,5S)-2-(benzyloxy)-5-(2-bromoethyl)-2,5-dihydrofuran underogo cis hydroxylation with OsO4 to form cis diol. Then, alcohols are protected with acetone in acid condition to form cyclic ether. Further, dehydrohalogenation takes place to form alkene. Further, ozonolysis followed by reduction with NaBH4 to form alcohol. Then, alcohol is converted to alkene by using barton Mc-coumbie reaction. Finally, benzyl group is removed by H2, Pd/C to form final product