Question

5. For the following set of reactions fill in the blank, whether it is the starting material needed, reagent(s) or product(s). Draw structures neatly and write any necessary reagents correctly. Some may include more than one step. Draw intermediates if want partial credit. (3 pts ea.) 1.NaH BV 3. HgSO4, H2SO4 1. TsCI 2. t-buOK d. Br 1. KOH 2.03 3.(CH3)2S 1. (sia), BH 2. HỒ0, NaOH 3. KOH 4. PCC 1. 1 eq HBr 2. mCPBA

Answer 1

5.

a.

H, Lindlar catalyst

Cis-alkene is obtained from the reduction of alkyne using Lindlar catalyst.

1.NaH 3. HgSO4, H2SO4

First, NaH deprotonates acetylene to form sodium acetylide. S_N2 attack of acetylide to 1-bromopentane leads to the formation of cyclopentyl acetylene. Hydrolysis of the cyclopentyl acetylene in presence of acid and mercury(II) catalysts yield the cyclopentyl methyl ketone as the product.

Yo TCL 1. Tscl Y 2. t-buOK

The product alkene can be obtained from the elimination reaction of tosylate. The tosylate can be obtained from the reaction of alcohol with tosyl chloride. Hence, the starting material is an alcohol.

* А . А. А. о 1. КОН 2. О, 3.(CH3),S +

The reactant undergo elimination reaction in presence of KOH. Then ozonolysis followed by dimethyl sulfide work up gives the ketone and the aldehyde.