Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1998-09-02
2000-07-18
Trinh, Ba K.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
502174, C07D30119, C07D30112
Patent
active
060909560
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an improved process for preparing epoxides from olefins using bis(triorganosilyl) peroxides in the presence of activators based on certain metallic acid derivatives.
While oxidants such as hydrogen peroxide HOOH or alkyl hydroperoxides ROOH have a firmly established place in organic synthesis, the synthetic potential of bis(triorganosilyl) peroxides (BTSPs), in particular the readily available bis(trimethylsilyl) peroxide (TMS.sub.2 O.sub.2), is restricted to a few applications.
Thus, BTSPs have been used as sources of "OH.sup.+ " for the stoichiometric electrophilic hydroxylation of carbanions, for instance aryllithium compounds, vinyl anions, .alpha.-sulfonyl-carbanions and also lithiated carboxylic acids and their amides (cf. Taddei and Ricci in Synthesis 1986, 633). The Baeyer-Villiger oxidation of ketones by BTSPs and the electrophilic hydroxylation of electron-rich aromatics in the presence of noncatalytic amounts of Lewis acids such as BF.sub.3, AlCl.sub.3 or SnCl.sub.4 are also known.
However, catalytic activation of BTSPs by metal complexes has hitherto only been successful in the case of the oxidation of primary and secondary alcohols to form aldehydes and ketones; the catalysts used here are pyridinium dichromate or the palladium complex PdCl.sub.2 (PPh.sub.3).sub.2. In contrast, attempts at the metal-catalyzed activation of BTSPs for the epoxidation of olefins have remained unsuccessful. Thus, Matsubara et al. in Tetrahedron Lett. 1983, 24, 3741 and in Bull. Chem. Soc. Jpn. 1985, 58, 844 reported unsuccessful attempts to activate TMS.sub.2 O.sub.2 by means of the acetylacetonates VO(acac).sub.2 and MoO.sub.2 (acac).sub.2. Instead of the hoped-for epoxidation of the allyl alcohols used, only isomerization of the olefinic double bond was observed.
It is an object of the present invention to provide an effective activator for the epoxidation of olefins using BTSPs.
We have found that this object is achieved by a process for preparing epoxides of the formula ##STR2## where R.sup.1 to R.sup.4 are identical or different and are hydrogen or substituted or unsubstituted alkyl, alkenyl, heteroalkyl, cycloalkyl, aryl or heteroaryl radicals, or the radicals R.sup.1 to R.sup.4 can also be linked to one another to form rings or are is substituents based on elements of main groups IV to VII of the Periodic Table of the Elements, from olefins of the formula ##STR3## wherein bis(triorganosilyl) peroxides of the formula unsubstituted or substituted by functional groups, are used as epoxidizing agents in the presence of activators based on metallic acid derivatives of the formula ##STR4## where M is a metal of transition groups IV to VII of the Periodic Table of the Elements, phosphine oxides, arsine oxides, stibine oxides, phosphoric triamides, formamides and pyridine N-oxides, groups, alkoxy groups, aryloxy groups, trialkylsilyl groups, hydroxyl groups, metallic anhydride groups of the formula --OMO.sub.x, carboxylic ester groups, sulfonic ester groups, phosphonic ester groups, carbonic ester groups, sulfuric ester groups, phosphoric ester groups, hydroperoxy groups, peroxyalkyl groups and triorganosilylperoxy groups, where two variables X can also represent a peroxo function, ligand L and one anionic ligand X may be linked to a chelating ligand either directly or via an alkylene bridge.
A prerequisite for a catalytically active activator for the purposes of the present invention is the ability of its oxo ligands [M.dbd.O] to react with the silyl peroxides of the R.sup.5 R.sup.6 R.sup.7 Si--OO--SiR.sup.5 R.sup.6 R.sup.7 type so as to convert them into a metal(silylperoxy) function [M(O.sub.2 --SiR.sup.5 R.sup.6 R.sup.7)] or a metal(peroxo) function [M(.eta..sup.2 --O.sub.2)], the latter with liberation of the corresponding siloxane R.sup.5 R.sup.6 R.sup.7 Si--O--SiR.sup.5 R.sup.6 R.sup.7. The decisive question for catalysis is whether silyl groups can, similarly to protons, migrate within the O-ligand regime in oxo(peroxo) complexes.
For this reason, latently coordinately unsat
REFERENCES:
patent: 3953362 (1976-04-01), Lines et al.
Synthesis Communication, cf. Taddei and Ricci in Synthesis 1986, 633-635.
Pergamon Press Ltd., Matsubara et al. In Tetrahedron Lett. 1983, vol. 24, pp. 3741-3744.
The Chemical Society of Japan, 58, 844-849 (1985) vol. 58, No. 3.
Synlett (Synles, 09365214); 1994; (4) pp. 255-256, Kyushu Univ.; Dep. Chem.; Fukuoka; 812; Japan, Irie et al: "Enantioselectives using hydrogen peroxide as a terminal oxidant".
Chemische Berichte, vol. 127, 1994, pp. 1201-1212, Sundermeyer et al "Homoscorpionate als tripodale . . . ".
Schulz Michael
Sundermeyer Jorg
Teles Joaquim Henrique
Wahl Gunter
BASF - Aktiengesellschaft
Trinh Ba K.
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