Chapter 10: Q44P (page 538)

Show how you would synthesize the following compounds from any starting materials containing no more than six carbon atoms.
a)
b)
c)

Short Answer

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Step by step solution

Grignard reaction

Grignard reaction occurs between the Grignard reagent and carbonyl-containing compounds like aldehydes, ketones, or epoxides. After hydrolysis results in forming 1^°,2^° , and 3^° alcohols with new C-C bonds. The obtained alcohol on heating with sulfuric acid gives alkene products.

Step 2: Synthesis of octan-3-ol

a) The target compound contains 11 carbon atoms, so the logical disconnections are two compounds containing one six-carbon fragment and one five-carbon fragment. These two compounds can be joined by using the Grignard reaction. The tetrasubstituted C=C is obtained by dehydration of3^° alcohol, obtained by two routes of Grignard reaction.

Synthesis of compound a

Synthesis of octan-1-ol

b) The target compound contains 12 carbon atoms, so the logical disconnections are two compounds containing six carbon fragments. Starting compound, we take Grignard reagent and aldehyde, and after hydrolysis, we get alcohol. This alcohol is heated by using H₂SO₄to get an alkene, and on reaction with mCPBA, compound with oxirane ring is obtained. The best way to get epoxide rings is from double bonds, and from alcohols, we get double bonds.

Synthesis of compound b

Step 4: Synthesis of 1-cyclohexylethanol

C) The target compound contains 14 carbon atoms, so the logical disconnections are two compounds containing six carbon fragments. Starting compound, we take Grignard reagent and ketone, and after that, by using Williamson ether synthesis, the ethyl group is put at the end to obtain the target compound.