The acylation of m-difluorobenzene (I) with 2-bromoacetyl bromide (II) by means of AlCl3 gives the phenacyl bromide (III), which is treated with ethylmercaptan (IV) and K2CO3 to yield the sulfanyl derivative (V). The fluorination of (V) with N-fluoro-4-methylpyridinium-2-sulfonate affords the difluoroacetyl derivative (VI). The methylenation of the carbonyl group of (VI) with trimethylsulfoxonium iodide provides the oxiranyl derivative (VII), which is opened with 1,2,4-triazole (VIII) and K2CO3, furnishing the propanol derivative (IX). The oxidation of the sulfanyl group of (IX) by means of H2O2 or MCPBA gives the corresponding sulfonyl derivative (X). Finally, the racemic mixture (X) is submitted to optical resolution by crystallization of the (+)-3-bromocamphorsulfonic acid. Alternatively, intermediate (VI) can be obtained as follows: The reaction of 2-chloro-2,2-difluoroacetic acid ethyl ester (XI) with ethylmercaptan (IV) by means of NaH gives the sulfanyl derivative (XII), which is finally condensed with 2,4-difluorobromobenzene (XIII) by means of BuLi to afford the desired intermediate (VI).

The acylation of m-difluorobenzene (I) with 2-bromoacetyl bromide (II) by means of AlCl3 gives the phenacyl bromide (III), which is treated with ethylmercaptan (IV) and K2CO3 to yield the sulfanyl derivative (V). The fluorination of (V) with N-fluoro-4-methylpyridinium-2-sulfonate affords the difluoroacetyl derivative (VI). The methylenation of the carbonyl group of (VI) with trimethylsulfoxonium iodide provides the oxiranyl derivative (VII), which is opened with 1,2,4-triazole (VIII) and K2CO3, furnishing the propanol derivative (IX). The oxidation of the sulfanyl group of (IX) by means of H2O2 or MCPBA gives the corresponding sulfonyl derivative (X). Finally, the racemic mixture (X) is submitted to optical resolution by crystallization of the (+)-3-bromocamphorsulfonic acid. Alternatively, intermediate (VI) can be obtained as follows: The reaction of 2-chloro-2,2-difluoroacetic acid ethyl ester (XI) with ethylmercaptan (IV) by means of NaH gives the sulfanyl derivative (XII), which is finally condensed with 2,4-difluorobromobenzene (XIII) by means of BuLi to afford the desired intermediate (VI).

The acylation of m-difluorobenzene (I) with 2-bromoacetyl bromide (II) by means of AlCl3 gives the phenacyl bromide (III), which is treated with ethylmercaptan (IV) and K2CO3 to yield the sulfanyl derivative (V). The fluorination of (V) with N-fluoro-4-methylpyridinium-2-sulfonate affords the difluoroacetyl derivative (VI). The methylenation of the carbonyl group of (VI) with trimethylsulfoxonium iodide provides the oxiranyl derivative (VII), which is opened with 1,2,4-triazole (VIII) and K2CO3, furnishing the propanol derivative (IX). The oxidation of the sulfanyl group of (IX) by means of H2O2 or MCPBA gives the corresponding sulfonyl derivative (X). Finally, the racemic mixture (X) is submitted to optical resolution by crystallization of the (+)-3-bromocamphorsulfonic acid. Alternatively, intermediate (VI) can be obtained as follows: The reaction of 2-chloro-2,2-difluoroacetic acid ethyl ester (XI) with ethylmercaptan (IV) by means of NaH gives the sulfanyl derivative (XII), which is finally condensed with 2,4-difluorobromobenzene (XIII) by means of BuLi to afford the desired intermediate (VI).