2-Allyl-4-chlorophenol

Removal of the one- carbon electrophilic formaldehyde (cf p T 10) leaves a chlorophenol (7) made by direct chlorination of (8). The long allyl chain of (8) cannot be put in by Friedel-Crafts alkylation or rearrangement will occur Cp T 9) so acylation and reduction are preferred. 

Typical procedure A mixture of p-chlorophenol (128 mg, 1 mmol), NaOH (40 mg, 1 mmol) and THF (10 mL) was stirred for 10 min allyldiisobutylteUuronium bromide (360 mg, 1 mmol) was then added. The reaction mixture was stirred for another 5 h at room temperature under nitrogen. Aqueous saturated NaHCOj solution was added and extracted with CH2CI2. The extract was dried over anhydrous MgS04 and concentrated in vacuo. The residue was chromatographed on sihca gel with 95 5 hexane-ethyl acetate as eluent to give a colourless oil of allyl p-chlorophenyl ether (145 mg, 86%). 

A displacement of the chlorine atom has been observed in the rearrangement of allyl 2,6-dichlorophenyl ether (XLI), which is converted to the normal product (XLII, 60% yield) along with a little (10% yield) of 2-allyl-6-chlorophenol (XLIII).46 Some hydrogen chloride is evolved, also. 

A mixture of 1 part by weight of p-chlorophenol, 1.1 parts of allyl bromide, 1.1 parts of potassium carbonate, and 1.3 parts of acetone is heated under reflux for 4 hours and then poured into water. The mixture is extracted with ether, and the ethereal solution is washed with dilute aqueous sodium hydroxide, then with water, dried over potassium carbonate, and distilled under vacuum. p-Chlorophenyl allyl ether is collected at 106-107°/12 mm., and the yield is quantitative. 

Chloro allyldiisobulyl 4-Chlorophenol 1 moles of NaOH in THF then telluronium bromide added phenol telluronium mixture stirred (5h.) under Nj to give allyl 4-chlorophenyl ether, bromide... 

By contrast, 4-chlorophenol undenA ent etherificatbn when reacted in tetrahydrofuran solution containing 1 mole of sodium hydroxide with allyldiisobutyltelluronium bromide under nitrogen during 5 hours to give allyl 4-chlorophenyl ether in 86% yield (ref. 41). 

Hexamethylenelmlne Methoxy PEG-10 intermediate. Insect repellents Hexahydrophthallc anhydride intermediate. Insecticides Allyl chloride Arsenic trichloride Benzophenone n-Butylamine t-Butylamine Cashew nut shell oil m-Chloroaniline 4-Chloro-3-nitrobenzotrifluoride 4-Chlorophenol Cumyl phenol Cyclopentanone 2,3-Dibromo-1 -propanol Dibutylamine Dicyclopentadiene Dinonyl phenol... 

Although solvent effect on the reaction rate had already been shown by White [15a] and Goering [15b] in 1958, later (in 1970) White reported the rate constants of the rearrangement of allyl p-tolyl ether at 170 °C using 17 solvents of different polarity [27]. The selected results are shown below. In protic solvent, the reaction is faster than that in aprotic solvent and the reaction in p-chlorophenol proceeds 300 times faster than that under neat conditions. 

In addition to the palladium catalysts mentioned, other transitional metal catalysts were explored and applied in this transformation as well. In 1995, Dunach and Olivero studied the nickel-catalyzed electrochemical reductive deprotection of allyl ethers. Among the various substrates, allyl-o-halogenophenols were tested as well. 2-Chlorophenol was produced from allyl-o-chlorophenol phenol was produced from allyl-o-bromophenol while 3-methyl-2,3-dihydrobenzofuran (33%) was produced from allyl-o-iodophenol together with phenol (52%). 

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