There are provided production processes for cyclic sulfone compounds of formula (2) or (4):
1
wherein the dashed lines represent that a double bond is present at one of three positions indicated; Ar and the wavy line are as defined below, characterized in that compounds of formula (1) or (3):
2
wherein Ar is aryl optionally having a substituent(s) and the wavy line represents either one of E/Z geometrical isomers or their mixture, is subjected to cyclization in the presence of an acid catalyst. These processes are excellent processes as the production processes for retinol from the viewpoints of raw material costs, intermediate purification, the number of steps, and the like.
提供了式(2)或式(4)环砜类化合物的生产工艺:
1
其中虚线表示在所表示的三个位置之一存在双键;Ar 和波浪线如下文所定义,其特征在于式(1)或(3)化合物:
2
其中 Ar 为芳基,可选具有一个或多个取代基,波浪线代表 E/Z 几何异构体之一或它们的混合物。从原料成本、中间纯化、步骤数量等角度来看,这些工艺都是
视黄醇生产工艺中的极佳工艺。