Problem 3: https://doi.org/10.1021/ja9093988 Answer to Problem 3: Hint. Assume the reaction can ONLY occur from the least sterically hindered side of the molecule. Draw or build a 3-dimentional conformation to support your answer. H CO₂Me H2 ? PtO2 HO A B с D H CO₂Me H CO₂Me H CO₂Me H CO₂Me HO HO HO

Department Final EXd Q1: Coibacin B is a natural product that exhibits potent anti-inflammatory activity and potential activity in the treatment of leishmaniasis, a disease caused by certain parasites. HAH H (a) Assign the configuration (R or S) of each chiral center in coibacin B. (b) Identify the number of possible stereoisomers for this compound, assuming that the geometry of the alkenes is fixed.

Sight along the C2-C3 bond of 2-methylbutane. Arrange the following conformation from lowest to highest energy. CH3 H CH3 CH3 CH3 H CH3 H HCH; CH3 HH H CH3 ㄒH CH3 H

Which chair represents the most stable conformation of Molecule A? A B b D d E e Molecule A Me ..Me 'Me Ме Chair conformations Me a) Me b) c) Me Me Me Me Me Me- -Me Me Ме Me d) Ме e) Ме Me Me- Ме Me Me Me

For the substituted cyclohexane compound shown, identify the atoms that will interact with the methyl group in a 1,3-diaxial fashion after rotation to the other chair conformation. BF Br E C HI A CI HF H3C- -HG HOJ HK CI H These atoms will interact with methyl in a 1,3-diaxial interaction. O D C O K MacBook Pro -FD

Identify the numbered carbon(s), if any, that have an attached H that is antiperiplanar to the Br atom in at least one accessible conformation. 1 2 O Br 1 N 3 4 5 6 8 8 3 O None 7 5 4

PS5-6. Draw all stereoisomers of the following molecule. (Hint: There are 4 enantiomer pairs and two meso achiral compounds for a total of 10 structures.) OH HO, HO Н OH

Be sure to answer all parts. i i Finish drawing the last possible stereoisomer of CH3CCHOHCHOHCCH3 and indicate which are enantiomers, diastereomers, or meso compounds. H H A CH3 OH HO OH -CH3 Enantiomers? A and B A and C A and D B and C HO B and D C and D none of the above C- -CH3 B H H -CH3 HO H Diastereomers? A and B A and C A and D B and C C B and D -CH3 H OH -CH3 C and D none of the above finish structure ... Meso? D A and B A and C A and D B and C B and D C and D none of the above

through the C2-C3 bond (identify which is which). 2. Draw cis-1,4-dibromocyclohexane in a chair conformation and determine the approximate strain energy using literature 1,3-diaxial strain energy values. SICE Innolaupsib to cont notam os To moitasto Jab nousmmoines

Draw the most stable chair conformation possible for this compound. Are there any 1,3-diaxial interactions in the most stable chair conformation ( H-H not included ) and please fill in the blank:  From the biomolecules surveyed, the compound is a(n)___________