1.Answer ALL parts.
(a)The following scheme depicts the synthesis of a bicyclic alcohol
D.(i)Give reagents for the conversion of alkene A into epoxide Band explain the stereoselectivityof the reaction.
[2](ii)Draw an accurate 3D representation of compound
C and explain any regioselectivity or stereo selectivity in the reactions leading to its formation.
[4](iii)Draw an accurate 3D representation of compound
D showing the expected stereo chemistry and explain any selectivity in the conversion of C to D.
[4](b)Draw accurate 3D representations of all intermediate compounds and the final product in the synthetic route shown below, explaining any stereo selective or regioselective reactions.
[10](c)Provide a synthesis of compound E from D-glucose drawing accurate 3Drepresentations of all intermediate compounds on the synthetic route and explaining any stereo selective or regioselective reactions.More than one step will be required.[10]
2.Answer ALL parts.(a)For both of the reactions below,give the mechanism and explain any selectivity.[2 × 5](i)(ii)(b)Give the product for each of the reactions below. Draw mechanisms for their formation, explaining each step and justifying any selectivity.
[2 × 10](i)(ii)PhPhOOPdCl2 catal ystOPhPhCH3OMeNBrOPd(0) catal ystEt3NMeNOBrNaOtBu (excess)PhMe, 110 oCPd(PPh3)4H3CIH2N+AC10H11N+BC14H22O3HOH3CPd(OAc)2 catal ystbenzoquinoneEtOCH3O
3.Answer ALL parts.(a)Theaza-enolateAreacts with cinnamyl bromide to give the threeproductsB,CandDin the ratios shown.CompoundDis isolated as a 1:1mixture ofdiastereoisomers.(i)IdentifyCandD, give mechanisms for their formationand rationalize theobservation thatCis the major product.[5](ii)Addition of AgBF4to the reaction medium results inBbeing formedalmost exclusively.With reference to the orbital interactions involved,provide an explanation for this observation.[7](iii)On heating,Bundergoes a thermal pericyclic process to giveDas the soleproductand as a singlediastereoisomer.Give an orbital explanation forthis reactionincludinga rationale for the observeddiastereoselectivity.
[8](b)Aza-enolateAalso reacts with benzaldehydeto give, after aqueous acidic work-up,a new productEas a singlediastereoisomer.
(i)IdentifyEandgive a mechanism for its formation. Include a full rationaleforthe stereochemistry observed in the product.[6](ii)CompoundEis treated with 2 eq. ofMeMgBr. Indicate the outcome ofthis reaction along with a rationale for any observed stereoselectivity.[4]END OF PAPER
