Chem 348 Final Exam Name _______________________Thursday May 6, 2010 Student #_____________________1) Consider the reaction AH(+) + H2O → A:( ‐) + H3O(+). For the following named acids: a) draw the structure of the acid, b) give the approximate pKa of the acid, c) give the name of the conjugate base, and d) draw the structure of the conjugate base. 16 points possible Acid Benzyl oxonium cation pKa Propyl propanoate pKa Pentane‐2,4‐dione pKa Allyl amine pKa Conjugate Base name: name: name: name: 2) Consider the reaction B:(‐) + H3O+ → BH(+) + H2O. For the following named bases: a) draw the structure of the base, b) draw the structure of the conjugate acid, c) give the approximate pKa of the conjugate acid, and d) give the name of the conjugate acid. 16 points possible Base 3‐Pentoxide anion Methanide anion p‐Ethoxyaniline Cyclopentadienyl anion Conjugate Acid pKa pKa pKa pKa name: name: name: name: 3) Consider the diketone hexane‐2,5‐dione, which under acidic conditions and high heat is converted to 2,5‐dimethylfuran. Devise a reasonable mechanism that accounts for this transformation using the curved arrow notation to account for all bond making and bond breaking. Remember this reaction is run under acidic condition so do not show any negatively charged species in your mechanism. 10 points possible 4) Benzaldehyde reacts with a 50 % solution of aqueous sodium hydroxide to give a 1:1 mixture of two products ‐ benzyl alcohol and benzoate ‐ in the Cannizzaro Reaction, a reaction you have not seen before but have the tools to rationalize. When deuterium is used for labeling, the following is observed: Devise a reasonable mechanism that accounts for this reaction using the curved arrow notation to account for all bond making and bond breaking. 10 points possible 5) Complete the following: Stereochemistry and regiochemistry are important. 30 points possible 6) Use molecular orbital analysis (sketch the HOMO/LUMO pi interactions) used to predict the Diels Alder reaction to predict if allyl anion OR allyl cation could react with ethylene in a thermal cycloaddition reaction. 8 points possible 7) Propose a synthesis of the following molecule starting from 4‐(3‐bromopropyl)benzaldeh y de. Use any reagents and starting materials necessary to accomplish this transformation . 10 points possible I pledge on my honor that this exam was completed by me, that I received no unauthorized help, and that I have not violated the honor code of the University. Please sign your name