A CHEM 245 student attempts the following reaction to synthesize the desired ether below, but he is unsuccessful: 2. H2SO4, CH3OH OCH3 desired ether racemic mixture (a) Use what you have learned in CHEM 241 to predict the structure of the major product he did collect: H2SO4, CH3OH (only one stereoisomer required) (b) Propose a reaction sequence that would be more likely to provide him with the desired ether product: OCH3 desired ether racemic mixture 3. Write out a complete mechanism for the reaction below: CH3 H3C H. CH3 H H Mechanism:

Alcohols are important for organic synthesis, especially in situations involving alkenes. The alcohol might be the desired product, or the OH group might be transformed into another functional group via halogenation, oxidation, or perhaps conversion to a sulfonic ester derivative. Formation of an alcohol from an alkene is particularly powerful because conditions can be chosen to produce either the Markovnikov or non-Markovnikov product from an unsymmetrical alkene. Using your reaction roadmap as a guide, show how to convert 4-methyl-1-pentene into 5-methylhexanenitrile. You must use 4-methyl-1-pentene and sodium cyanide as the source of all carbon atoms in the target molecule. Show all reagents needed and all molecules synthesized along the way.

Nonconjugated , -unsaturated ketones, such as 3-cyclohexenone, are in an acid-catalyzed equilibrium with their conjugated , -unsaturated isomers. Propose a mechanism for this isomerization.

When cis-2-decalone is dissolved in ether containing a trace of HCl, an equilibrium is established with trans-2-decalone. The latter ketone predominates in the equilibrium mixture. Propose a mechanism for this isomerization and account for the fact that the trans isomer predominates at equilibrium.

Draw a structural formula for the major organic product of each reaction and specify the most likely mechanism by which each is formed. (g) CH3CH2ONa++CH2=CHCH2Clethanol

Following is the structure of miconazole, the active antifungal agent in a number of over-the-counter preparations, including Monistat, that are used to treat vaginal yeast infections. One of the compounds needed for the synthesis of miconazole is the trichloro derivative of toluene shown on its right. (a) Show how this derivative can be synthesized from toluene. (b) How many stereoisomers are possible for miconazole?

Please give the main substitution product for each of the following reactions, and indicate the dominant mechanism:      (a)     1-bromopropane   +   NaOCH3   →      (b)     3-bromo-3-methylpentane   +   NaOC2H5   →

5) Predict the product and provide a mechanism and stereochemistry of the following reaction. 0 H₂SO4 + CH3OH- 1

7. What effect would you expect the following changes to have on the rate of the SN2 reaction of 1-iodo-2-methylbutane with cyanide ion? (a) The CN' concentration is halved, and the 1-iodo-2-methylbutane concentration is doubled. (b) Both the CN1 and the 1-iodo-2-methylbutane concentrations are tripled.

Complete each reaction scheme below with the starting material required to give the product shown as the only major product following the indicated sequence of reactions. Each individual reaction in the sequence must serve a purpose and must result in a product that is different from the corresponding starting material. 1) i) LIAIH, ii) H30* 2) TSCI, pyridine OTs