PURPOSE: To prepare the titled compound useful as vitamin E, without using optical resolution process, in high yield in an industrial scale, through nine steps from natural phytol used as the starting substance via novel intermediates, novel α-tocopherylquinone, etc.
CONSTITUTION: The compound of formula II or its enantiomer is prepared by the enantioselective oxidation of the compound of formulaI. The compound of formula II is subjected to reductive cleavage to the compound of formula III, protection of the 3-OH, oxidation of the 1-OH to aldehyde, and reaction with the compound of formula VI (X is halogen) to obtain the compound of formula VII (R1WR3 are protecting group), which is converted to the compound of formula IX by dehydration and reduction of the resultant double bond. X by the removal of the compound of formula X is obtained from the compound of formula IX by the removal of the protecting groups R1WR3 followed by oxidation. Cyclization of the compound of formula X affords the objective compound of formula X. The enantiomer of the objective compound can be prepared from the enantiomer of the compound of formula II. The compounds of formula IIW formula IX excluding the formula VI, and their enentiomers are novel compounds.
AKASAKA KOUZOU
YAMAGISHI YOUJI
| JPS52136102A | 1977-11-14 | |||
| JPS4988877A | 1974-08-24 |