Q41E - Organic Chemistry (Mcmurry)

Question

How would you prepare the following compounds from 1-phenylethanol?

(a) Methyl 1-phenylethyl ether       (b) Phenylepoxyethane

(c) tert-Butyl 1-phenylethyl ether    (d) 1-Phenylethanethiol

Step-by-Step Solution

Answer

(a) 

(b) 

(c) 

(d) 

Step-by-step Solution Step 1: Preparation of Methyl 1-phenylethyl ether from phenylethanol

(a)1-phenylethanol on treating with sodium hydride (NaH) then sodium 1-phenylethanolate is formed which on further react with CH₃Br to give desired product as shown below:

Preparation of Methyl 1-phenylethyl

Step 2: Preparation of Phenylepoxyethane from phenylethanol

(b) 1-phenylethanol on reacting with ${\mathrm{POCl}}_3$in the presence of a catalyst pyridine gives styrene which on further react with ${\mathrm{RCO}}_3\mathrm{H}$ to form the desire product as shown below:

Preparation of Phenylepoxyethane

Step 3: Preparation of tert -Butyl 1-phenylethyl ether from phenylethanol

During alkoxymercuration reaction, an alkenes reaction with suitable mercury salt and an alcohol occurs. The reagent used in the reaction is NaBH₄  (sodium borohydride) which will undergo a reductive demercuration and yield corresponding ethers.

(c)1-phenylethanol on treatment with alkoxymercuration –demercuration reaction gives tert-Butyl 1-phenylethyl ether as the desired product as shown below:

Preparation of tert-Butyl 1-phenylethyl ether

Step 4: Preparation of 1-Phenylethanethiol from phenylethanol

(d) 1-phenylethanol on treating with ${\mathrm{PBr}}_{3, }$gives 1-bromoethylbenzene which on further react with thiourea in the presence of water to give desired product as shown below in the figure:

Preparation of 1-Phenylethanethiol