PROCESS FOR PRODUCING HYDROXYL-PROTECTED /7E,9Z/-7,9-ALKADIEN-1-OLS AND DERIVATIVES

摘要

Preparation of E7/Z9-alkadien-1-ols of the formula I …… (where R<1> = C1-C8-alkyl, R<2> = H or a base-stable hydroxyl protecting group) by reacting an optionally OH-protected 7-hydroxyheptanal II… OHC-(CH2)6-OR<2> II… with a phosphorus ylide III …… in which… R<3> and R<4> denote a low-molecular weight alkyl group or are connected to one another to give an optionally C1-C4-alkyl-substituted dioxane or dioxolane system and… R<5> stands for alkyl, cycloalkyl or optionally substituted phenyl,… in a Wittig reaction to give compounds of the formula IV …… which are converted by the action of acid into the trans 2-nonenal V …… which is reacted by means of a further Wittig reaction with a phosphorus ylide VI …… in which R<1> and R<5> have the abovementioned meaning, to give the E7/Z9-alkadienols which are obtained from the reaction mixture in a manner known per se.