NOVEL SULFONE DERIVATIVES AND PROCESS FOR PRODUCING THESE

摘要

A process for producing a cyclic sulfone compound represented by the formula (2) (2) or the formula (4) (4) (wherein the three broken lines indicate that one of the three bonds is a double bond; Ar represents optionally substituted aryl; and the wavy line indicates that the compound is either of the geometric E and Z isomers or a mixture of these), characterized by cyclizing a compound represented by the formula (1) (1) or the formula (3) (3) (wherein Ar and the wavy line have the same meanings as defined above) in the presence of an acid catalyst. This process is an excellent process for retinol production from the standpoints of the cost of starting materials, intermediate purification, number of steps, etc.