Process for the preparation of oxovinylionol and its o-protected derivatives
AssigneeBASF SE
InventorsHansgeorg Ernst, Michael Puhl, Stefan Benson, Wolfgang Siegel
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Abstract
The present invention relates to the preparation of oxovinylionol and its O-protected derivatives of the formula I in which R is hydrogen or an OH protecting group, for example a group Si(Ra)3, by reacting a compound of the general formula II in which R has the meanings given above for formula I, i.e. β-vinyl ionol (formula II, R=hydrogen) or an O-protected derivative thereof (formula II, R═OH protecting group) with an oxidant in the presence of at least one transition metal, where the oxidant comprises at least one oxygen-containing compound which is selected from among hydrogen peroxide and organic hydroperoxides.
Claims24
-23. (canceled)
A process for the preparation of oxovinylionol and its O-protected derivatives of the formula I
- in which R is hydrogen or an OH protecting group, wherein β-vinyl ionol or an O-protected derivative thereof of the formula II in which R has the above-mentioned meanings is reacted with an oxidant in the presence of at least one transition metal, where the oxidant comprises at least one oxygen-containing compound selected from among hydrogen peroxide and organic hydroperoxides.
The process according to claim 34, wherein the ligand has at least one group suitable for coordination with the transition metal which is selected from among oxazole, 2,2-bipyridine and 1,10-phenanthroline groups.
The process according to claim 34, wherein the ligand is used in an amount of from 0.5 to 2 mol per mole of transition metal.
A compound of the general formula III
- in which R is hydrogen or an OH protecting group, and R′ is hydrogen, alkyl or arylalkyl.
A process for the preparation of a phosphonium salt of the formula IVa
- in which Ph is phenyl, which comprises:
- a″) providing a silyl enol ether of the formula V
- in which Ra in group Si(Ra)3 can be identical or different and independently of one another are C1-C4-alkyl and Rs is an acid-cleavable OH protecting group;
- b″) successively reacting the compound of the formula V with a peroxo carboxylic acid and reacting the oxidation product with hydrobromic acid, which gives a compound of the formula VIa:
- c′) reacting the compound of the formula VIa with triphenylphosphane, which gives a compound of the formula IVa.
Dependencies are inferred from the claim text.