Patent ID: 8865900

Claim:
A process for preparing a sulfone comprising the steps of: (a) reacting a halomethyl substrate of general formula (1a) or (1b), wherein R 1 is halogen, wherein R 2 and R 3 each independently stand for an alkyl with 1 to 12 carbon atoms or an alkenyl with 1 to 12 carbon atoms or a cycloalkyl with 3 to 7 carbon atoms or a cycloalkenyl with 3 to 7 carbon atoms or an aryl with 6 to 10 carbon atoms or an aralkyl with 7 to 12 carbon atoms or wherein R 2 and R 3 form a ring together with the carbon atom to which they are bound, wherein R 4 is an alkyl or alkenyl group with 1 to 4 four carbon atoms and wherein R 5 is an alcohol protecting group, with 1-methyl-1H-tetrazole-5-thiol or a salt thereof to obtain a compound of general formula (2a) or (2b), respectively; and thereafter, (b) oxidizing the compound of general formula (2a) or (2b) to give a sulfone of general formula (3a) or (3b), respectively, wherein R 2 , R 3 and R 4 in formulas (2a), (2b), (3a) and (3b) are the same as previously defined for formulas (1a) and (1b).