Sulphuryl chloride as an electrophile. Part IV. Steric hindrance to activation by the methoxy-group

Abstract

The rates of reaction of sulphuryl chloride with a number of aromatic ethers have been studied in chlorobenzene solution. The additivity principle, which has been shown to hold in a number of examples of this reaction, fails when two substituents are placed ortho to the methoxyl group in anisole. 2,3,4,6-Tetramethylanisole substitutes chlorine at a similar rate to that of 3-methylanisole, its calculated rate coefficient being 2000 times the experimental value. Neither increasing the size of the alkyl group attached to the oxygen atom, nor using only one ortho-substituent, brought about any detectable effect due to steric factors.