Process for producing vitamin A or its carboxylic acid esters, and intermediate compounds useful for the process

Abstract

A process for producing vitamin A represented by the formula ##STR1## which comprises treating a compound represented by the formula ##STR2## wherein R.sup.1 represents an aryl group which may be substituted, R.sup.21 and R.sup.22 each represents a hydrogen atom or a lower alkanoyl group, R.sup.3 represents an acetal-type protective group for a hydroxyl group, and X represents a halogen atom, with a base; and novel intermediate compounds useful for the above process.

Dependencies are inferred from the claim text.