| PATENT ASSIGNEE'S COUNTRY | Germany |
| UPDATE | 03.00 |
| PATENT NUMBER | This data is not available for free |
| PATENT GRANT DATE | 14.03.00 |
| PATENT TITLE |
Process for catalytic addition of nucleophiles to alkynes or allenes |
| PATENT ABSTRACT |
A process for the catalytic addition of nucleophilic agents to alkynes or allenes to form alkenes substituted by the nucleophile which may further react with the nucleophile and/or isomerize comprises using a catalyst comprising a wholly or partly ionized complex of univalent gold. |
| PATENT INVENTORS | This data is not available for free |
| PATENT ASSIGNEE | This data is not available for free |
| PATENT FILE DATE | 15.06.98 |
| PATENT CT FILE DATE | 06.12.96 |
| PATENT CT NUMBER | This data is not available for free |
| PATENT CT PUB NUMBER | This data is not available for free |
| PATENT CT PUB DATE | 19.06.97 |
| PATENT FOREIGN APPLICATION PRIORITY DATA | This data is not available for free |
| PATENT REFERENCES CITED |
Journal of Organic Chemistry by Fuduka et al. 56 pp. 3729-3731 1991. JAPIO1992-095039 abs of JP04095039 by Yukitoshi. |
| PATENT CLAIMS |
We claim: 1. A process for the catalytic addition of nucleophilic agents selected from the group consisting of water, alcohols having from 1 to 30 carbon atoms, carboxylic acids having from 1 to 30 carbon atoms, and compounds containing a combination of alcohol and carboxylic acid groups to alkynes or allenes thereby forming alkenes substituted by the nucleophile which may further react with the nucleophile and/or isomerize, which comprises using a catalyst comprising a wholly or partly ionized complex of univalent gold containing a complex cation of formula (1) L--Au.sym. (1) wherein the ligand L represents a building block of the formula ##STR6## and R.sup.1, R.sup.2 and R.sup.3, each independently of the other, represent a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms which may be bridged and may optionally be attached to E via an oxygen atom or via a nitrogen atom; E is phosphorus, arsenic or antimony; R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each, independently, hydrogen or a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms, a corresponding alkoxy group or ester group, a nitro group, a cyano group or a halogen. 2. A process as claimed in claim 1, wherein nucleophiles are added to alkynes having from 2 to 60 carbon atoms or to allenes having from 3 to 60 carbon atoms in the presence of a catalyst of the formula 2 L--Au.sym.X.crclbar. (2) wherein the ligand L represents a building block of the formula ##STR7## and R.sup.1, R.sup.2 and R.sup.3, each independently of the other, represent a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms which may be bridged and may optionally be attached to E via an oxygen atom or via a nitrogen atom; E is phosphorus, arsenic or antimony; R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each, independently, hydrogen or a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms, a corresponding alkoxy group or ester group, a nitro group, a cyano group or a halogen, and X is an anion. 3. A process as claimed in claim 2, wherein water, alcohols having from 1 to 30 carbon atoms or carboxylic acids having from 1 to 30 carbon atoms are added to alkynes having from 2 to 20 carbon atoms or allenes having from 3 to 20 carbon atoms in the presence of a catalyst of the formula 2a ##STR8## where R.sup.1, R.sup.2 and R.sup.3 are alkyl or aryl radicals having from 1 to 10 carbon atoms, which may be substituted or unsubstituted and may each be attached to E via an oxygen atom, E is phosphorus, and Z is a weakly coordinating or noncoordinating anion. 4. A process as claimed in claim 3, wherein the catalyst used has the formula 2a where Z is a weakly coordinating or noncoordinating anion selected from the group consisting of nitrate, sulfate, azide, sulfonate, sulfinate, alcoholate, phenolate, carboxylate, perchlorate, tetrafluoroborate, hexafluoroantimonate, hexafluorophosphate and tetraphenylborate. 5. A process as claimed in claim 1, wherein the catalyst is formed in situ in the reaction mixture. 6. A process as claimed in claim 1, wherein the catalyst is formed in situ by reacting, with a Lewis acid, a neutral gold(I) complex of the formula 3 L--AuX (3), wherein the ligand L represents a building block of the formula ##STR9## and R.sup.1, R.sup.2 and R.sup.3, each independently of the other, represent a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms which may be bridged and may optionally be attached to E via an oxygen atom or via a nitrogen atom; E is phosphorus, arsenic or antimony; R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each, independently, hydrogen or a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms, a corresponding alkoxy group or ester group, a nitro group, a cyano group or a halogen, and X is a radical that fonns an anionic complex with said Lewis acid. 7. A process as claimed in claim 1, wherein the catalyst is formed in situ by reacting a neutral gold(I) complex of the formula 3 L--AuX (3), wherein the ligand L represents a building block of the formula ##STR10## and R.sup.1, R.sup.2 and R.sup.3, each independently of the other, represent a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms which may be bridged and may optionally be attached to E via an oxygen atom or via a nitrogen atom; E is phosphorus, arsenic or antimony; R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each, independently, hydrogen or a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms, a corresponding alkoxy group or ester group, a nitro group, a cyano group or a halogen, and X is a Cl, Br or I, with a silver salt containing a noncoordinating anion. 8. A process as claimed in claim 1, wherein the catalyst is formed in situ by reacting a neutral gold(I) complex of the formula 4 L--Au--R' (4), wherein the ligand L represents a building block of the formula ##STR11## and R.sup.1, R.sup.2 and R.sup.3, each independently of the other, represent a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms which may be bridged and may optionally be attached to E via an oxygen atom or via a nitrogen atom; E is phosphorus, arsenic or antimony; R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each, independently, hydrogen or a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms, a corresponding alkoxy group or ester group, a nitro group, a cyano group or a halogen, and R' is alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl or aryl, with a Bronsted acid HY, where Y is a weakly coordinating or non-coordinating anion, or with a Lewis acid. 9. A process as claimed in claim 1, wherein the catalyst is formed by dissociation of a stable gold(I) complex of the formula 3 L--AuX (3), wherein the ligand L represents a building block of the formula ##STR12## and R.sup.1, R.sup.2 and R.sup.3, each independently of the other, represent a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms which may be bridged and may optionally be attached to E via an oxygen atom or via a nitrogen atom; E is phosphorus, arsenic or antimony; R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each, independently, hydrogen or a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms, a corresponding alkoxy group or ester group, a nitro group, a cyano group or a halogen, and X is a radical which forms an anion in a polar medium. |
| PATENT DESCRIPTION |
DESCRIPTION The present invention relates to a process for the addition of nucleophiles to alkynes and allenes in the presence of a wholly or partly ionized complex of univalent gold applicable to a wide range of alkynes and allenes. The addition of nucleophiles to alkynes is catalyzed by acids, bases or transition metal complexes (cf. Houben-Weyl, Methoden der organischen Chemie, Vol. 6/3, p. 233, p. 90, Vol. 5/2a, p. 738, Vol. 6/1d, p. 136 and Vol. 7/a, p. 816). The acid catalysis is usually restricted to the addition of nucleophiles to activated, electron-rich alkynes (such as acetylene ethers, R--C.tbd.C--OR', acetylene thioethers, R--C.tbd.C--SR' and acetyleneamines, --C.tbd.C--NR'.sub.2). Alcohols can be added to unactivated alkynes by base catalysis (in the presence of KOH or alcoholate). This is the method of choice for the monoaddition of alcohols to alkynes to form enol ethers. The addition of nucleophiles to alkynes is also catalyzed by transition metal complexes. Generally, they are complexes of metals of groups 11 and 12 (according to the currently applicable IUPAC nomenclature of inorganic chemistry). Rhodium, ruthenium, palladium and platinum catalysts have also been used in individual cases. According to J. S. Reichert, H. H. Bailey, J. A. Nieuwland, J. Am. Chem. Soc., 45 (1923), 1552, and G. F. Hennion, J. A. Nieuwland, J. Am. Chem. Soc., 57 (1935), 2006, mercury(II) compounds, usually in combination with a Lewis and a Brbnsted acid, are the most active catalysts for the addition of nucleophiles to alkynes. Such Hg(II) catalysts can be used to add water, alcohols and carboxylic acids to alkynes. These catalysts have very general utility, but their scope of application is limited by the toxicity of mercury and by the relatively low turnover numbers (<500), ie. the ratio of the number of moles of product formed per mole of catalyst. W. Reppe, Ann., 601 (1956), 81, describes zinc(II) and cadmium(II) compounds for use as catalysts for the addition of carboxylic acids and phenols to alkynes. Gold(III) compounds such as sodium tetrachloroaurate (NaAuCl.sub.4) have hitherto been described for use as catalysts for the addition of water or alcohols to alkynes only once (Y. Fukuda, K. Utimoto, J. Org. Chem., 56 (1991), 3729). Gold(I) compounds have evidently hitherto not been used as ctalysts for the addition of nucleophiles to alkynes. As can be seen from the description of the background art, there are numerous existing processes for the addition of nucleophiles to alkynes, but they all have a limited range of applications. The hitherto preferred mercury catalysts, in particular, have the disadvantage of toxicity and relatively low turnover numbers, so that a high catalyst consumption had to be tolerated or appreciable amounts of byproducts were formed. It is an object of the present invention to propose a universally useful catalytic process for the addition of nucleophilic agents to alkynes or allenes and, more particularly such a process as does not have the disadvantages described and which even makes possible the addition of weak nucleophiles and the addition to unactivated alkynes. We have found that this object is achieved according to the invention by a process for the catalytic addition of nucleophilic agents to alkynes or allenes to form alkenes substituted by the nucleophile which may further react with the nucleophile and/or isomerize, which comprises using a catalyst comprising a wholly or partly ionized complex of univalent gold. Since the complexes have to be at least partly present in ionized form, it is assumed that the catalytic effect is due to a complex cation of the formula 1 L--Au.sym. (1) where the ligand L can represent the building blocks ##STR1## and where R.sup.1, R.sup.2 and R.sup.3 independently of the others represent substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radicals having from 1 to 30 carbon atoms which may be bridged and may optionally be attached to E via an oxygen atom or via a nitrogen atom, E is phosphorus, arsenic or antimony, and R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are each hydrogen or a substituted or unsubstituted aliphatic, cycloaliphatic, aromatic, heteroaromatic or araliphatic radical having from 1 to 30 carbon atoms, a corresponding alkoxy group or ester group or alternatively a nitro group, cyano group or halogen, and the ligand L can also have been incorporated into a polymer. Accordingly, the catalysts used are in particular complexes of the formula 2 L--Au.sym.X.crclbar. (2) where the ligand L is as defined above and X is an anion, especially a weakly coordinating or noncoordinating anion. The process of the present invention is of particular importance for the addition of water, alcohols having from 1 to 30 carbon atoms or carboxylic acids having from 1 to 30 carbon atoms to alkynes having from 2 to 60 carbon atoms or to allenes having from 3 to 60 carbon atoms in the presence of a catalyst of the formula 2a ##STR2## where R.sup.1, R.sup.2 and R.sup.3 are substituted or unsubstituted alkyl, cycloalkyl, aryl or aralkyl radicals having in each case from 1 to 30, preferably from 1 to 10, carbon atoms, which may be bridged and may each be attached to E via an oxygen atom or via a nitrogen atom, E is arsenic, antimony or especially phosphorus, and X is an anion, especially a weakly coordinating or noncoordinating anion. Preference is given to complexes of the formula 2a where the radicals R.sup.1, R.sup.2 and R.sup.3 are substituted or unsubstituted primary, secondary or tertiary alkyl radicals or substituted or unsubstituted aryl radicals such as pyridyl, naphthyl or in particular phenyl radicals or substituted or unsubstituted alkoxy or aryloxy radicals. Coordinating anions for the purposes of this invention include for example chloride, bromide and iodide; weakly coordinating anions include for example nitrate, sulfate, azide, cyanate, sulfonates such as tosylate, methanesulfonate, trifluoromethanesulfonate, sulfinates such as -benzenesulfinate, alkoholates such as methanolate, ethanolate or -2,2,2-trifluoroethanolate, phenolate, carboxylates such as acetate or -trifluoroacetate; and noncoordinating anions include for example perchlorate, tetrafluoroborate, hexafluoroantimonate, hexafluorophosphate or tetraphenylborate. The process of the present invention performs particularly well when the catalyst used has the formula 2a where X is a weakly coordinating or uncoordinating anion selected from the group consisting of nitrate, sulfate, azide, sulfonate, sulfinate, alcoholate, phenolate, carboxylate, perchlorate, tetrafluoroborate, hexafluoroantimonate, hexafluorophosphate and tetraphenylborate. The aforementioned catalytically active ionized gold(I) complexes are generally not stable in the free form and are therefore generally prepared in situ. Several well known methods are available for this in the examples which follow L is always as defined above): 1. In situ reaction of a stable gold(I) complex of the formula 3 where R' is alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl or aryl, with a Bronsted acid HY, where Y is a weakly coordinating or noncoordinating anion, or with a Lewis acid, especially with BF.sub.3 as etherate or methanolate. 4. Dissolution of a stable gold(I) complex of the formula 3 L--AuX (3), where X is a radical capable of forming an anion, in a polar medium in which the complex can dissociate into free or solvated ions. Similarly, any other reaction whereby the cation of the formula 1 can be generated in situ is suitable. The ionized gold(I) complexes of the formula 2 to be used as catalysts and their starting compounds of the formulae 3 and 4 are known from the literature, for example from D. I. Nichols and A.S. Charleston, J. Chem. Soc. (A) (1969), 2581, U.S. Pat. No. 3,661,959, and Inorganic Synthesis 26 (1989) 325, hereby cited for reference. Suitable nucleophilic agents, or nucleophiles for short, for the novel catalyzed addition to alkynes or allenes are the well known agents capable of electron donation. Suitable compounds include in particular water, alcohols having from 1 to 30, preferably from 1 to 10, carbon atoms, such as methanol, ethanol, 2-propanol or t-butanol, phenols, carboxylic acids having from 1 to 20, preferably from 1 to 10, carbon atoms, such as formic acid, acetic acid or acrylic acid, thiols, sulfonic acid, phosphoric acids, hydrogen halides or else compounds containing a combination of the functionalities mentioned. Suitable alkynes or allenes for the nucleophilic addition of the invention are any compounds having, respectively, from 2 to 60 and 3 to 60 carbon atoms. However, preference is given to alkynes or allenes having respectively from 2 to 8 and from 3 to 8 carbon atoms and alkynes having functional groups. Examples of suitable starting materials include accordingly preferably alkynes (terminal or internal) from acetylene through octyne, allene, propargyl alcohol, 1-butyn-3-ol or 2-butyne-1,4-diol. The addition of the nucleophilic agents, for example methanol, to an alkyne is effected in a conventional manner according to the following scheme: ##STR3## The resulting enol ether generally adds a further molecule of methanol to form the compound ##STR4## In the case of the addition of water the enol then immediately forms the corresponding ketone by isomerization. Also possible are further reactions with ring formation, as shown below. These reactions are all known and not a particular feature of the present process. In what follows, some additions catalyzed according to the invention are recited to exemplify possible applications. ##STR5## The addition catalyzed according to the invention can be carried out not only in the presence but also in the absence of an inert solvent. Preference is given to the procedure without solvent, ie. using the nucleophile and/or the alkyne as reaction medium. The molar ratio of nucleophile to alkyne or allene can be chosen within the range from 0.01 to 10000. Preference is given to ratios within the range from 0.9 to 100. Particular preference is given to ratios within the range from 1 to 5. The reaction temperature is within the range from -30 to +150.degree. C., preferably within the range from 0 to 80.degree. C. Particular preference is given to temperatures within the range from 20 to 60.degree. C. The addition can be carried out at atmospheric pressure, reduced pressure and elevated pressure. The molar ratio between the gold(I) complex, which is used in deficiency, and the sum of the reactants can be chosen within the range from 0.1 to 10.sup.-8. Preference is given to ratios within the range from 0.01 to 10.sup.-5. The gold(I) complex is not consumed during the addition reaction and can be recovered from the reactor effluent after the reaction product has been distilled and recycled into the reaction stage, so that the reaction can also be carried out continuously. Excellent turnover numbers are obtained, even at low conversion in a single pass, since virtually no byproducts are formed and the process is thus notable for high selectivity. Finally, the gold(I) complex catalyst is stable under the reaction conditions, whereas, for example, the gold(III) complexes mentioned in the introductory part of this description tend to shed gold and hence to form a mirror of gold on the reactor surfaces. |
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| PATENT PHOTOCOPY | Available on request |
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