Backa. Propose a mechanism for the following reaction.
2 (CH3)2C=CH–CH3 + cat. H+ → 2,3,4,4-tetramethylhex-2-ene
b. Show the first three steps (as far as the tetramer) in the BF3–catalyzed polymerization of propylene to form polypropylene.
Develop syntheses for the following compounds, using acetylene and compounds containing no more than four carbon atoms as your organic starting materials.
(a) 3-methylnon-4-yn-3-ol (“3-ol” means there is an OH group on C3.)
Develop syntheses for the following compounds, using acetylene and compounds containing no more than four carbon atoms as your organic starting materials.
(b) cis-1-ethyl-2-methylcyclopropane
Propose mechanisms to explain the opposite regiochemistry observed in the following two reactions.
Show how you would accomplish the following synthetic conversions.
(c) 2−methylcyclohexanol → 1−bromo−1−methylcyclohexane
Work backward to show how the cyclopropane would be synthesized from the chloroalkane shown.
For each of the following target molecules, design a multistep synthesis to show how it can be prepared from the given starting material:
b.
Identify A–E.
Using cyclooctyne as your starting material, show how you would synthesize the following compounds. (Once you have shown how to synthesize a compound, you may use it as the starting material in any later parts of this problem.)
(h)
For each of the following target molecules, design a multistep synthesis to show how it can be prepared from the given starting material:
a.
A, a compound with molecular formula C6H10, contains three methylene units. A reacts with one equivalent of H2 over Pd/C to yield B. A reacts with aqueous acid to form a single product, C, and undergoes hydroboration/oxidation to form a pair of enantiomers, D and E. Ozonolysis of A followed by reaction with dimethyl sulfide forms F with molecular formula C6H10O2. Provide structures for A–F.
Starting with cyclohexene, how can the following compounds be prepared?
c. dicyclohexyl ether
Fill in each box with the appropriate reagent:
c.
a. Starting with 3-methyl-1-butyne, how can you prepare the following alcohols?
2. 3-methyl-1-butanol
b. In each case, a second alcohol would also be obtained. What alcohol would it be?
Write the appropriate reagent over each arrow.