Dr. P. Wipf CHEM 2320 1/26/08 NAME: SID: Sample ExamSample Exam I (20 pts) ___________ II (15 pts) ___________ III (25 pts) ___________ IV (10 pts) ___________ V (16 pts) ___________ VI (14 pts) ___________ VII (Bonus) ___________ TOTAL (100 pts) ___________ This Exam has 8 pages.Page 2 Problem I. (20 pts) Predict the major products for the following reactions. Draw all products in the 3D conformations and make it clear what the product configuration is. a) Br 1. t-BuLi (2 equiv)2. PhCHO b) Br1. Mg, Et2O2. Me2CHCN c) MeOMeOOTBDMS1. n-BuLi 2. BrCH2CH=CMe2 d) Et CHOOMe+ButOLi e) HOBnOMgBr2•OEt2MgBrMeO2C f) O1. sec-BuLi2. (-)-MeOBIpc23. BF3•OEt24. 5. NaOH, H2O2HO OPMBPage 3 Problem II. (15 pts) Suggest reagents for the following transformation. Explain the stereoselectivity of the reaction (draw an appropriate transition state model). Suggest how you would obtain the other syn-aldol product and explain the difference in the stereoselectivity. CHO+ONPhOONOOHOOPhPage 4 Problem III. (25 pts) Propose methods for the following conversions. Use reagents as required. a) NOAcOAcCO2BnNOAcCO2BnCOPh b) NHHMeOOMeHNHHMeOMeH c) OO d) OO e) OOOH(Bonus points: what is the name of this reaction?)Page 5 Problem IV. (10 pts) What reagents would accomplish the following transformations (more than one might be needed)? a) OMeOHO b) NHMeONHMe c) SSHH d) HO OHHO O f) OOHPage 6 Problem V. (16 pts) The following transformation a) affords the diol in a 10:1 diastereoselection. In contrast, reaction b) does not occur selectively. Propose a mechanism for this transformation that accounts for these stereochemical results. a) OOH+B(OH)2OHOH10 : 1 b) OMeO+B(OH)2MeOOH1 : 1Page 7 Problem VI. (14 pts) Give a typical example for a Lindlar Hydrogenation (with reagents).Page 8 Problem VII. (Bonus) Draw the mechanism of a typical Ritter
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