Methods for cross-metathesis of terminal olefins

Details Methods for cross-metathesis of terminal olefins Methods for cross-metathesis of terminal olefins

2000-01-26

2001-10-23

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S336000, C502S155000, C556S021000, C556S022000, C556S136000

Reexamination Certificate

active

06306988

ABSTRACT:

BACKGROUND
The recent development of well-defined ruthenium and molybdenum metathesis catalysts has generated renewed interest in methods for selective cross-metathesis of terminal olefins. For example, Crowe et al. have demonstrated that &pgr;-substituted terminal olefins such as styrene and actylonitrile can be used to efficiently functionalized terminal olefins. Crowe has also reported a useful terminal olefin cross-coupling procedure utilizing nucleophillic species such as allyltrimethylsilane. More recently, Blechert et al. have shown that certain sterically hindered terminal olefins do not undergo self-metathesis and can be functionalized with a number of commercially available terminal olefins using ruthenium and molybdenum catalysts. The homologation of homoallylglycine derivatives has been reported by Gibson et al. Finally, both cross yne-ene and ring-opening cross metathesis reactions using Ru and Mo catalysts have been demonstrated. Unfortunately, these reactions tend to be slow, non-selective with relatively low product yields. As a result, large scale reactions for commercial applications are generally unfeasible using prior known methods.
SUMMARY OF THE INVENTION
The present invention relates to a method for making disubstituted internal olefin products from a first terminal olefin and a second terminal olefin. In general, the first terminal olefin is reacted with itself to form a dimer intermediate. The dimer is then reacted with the second olefin to yield the disubstituted internal olefin product. A schematic illustration of this concept is as follows:
XCH=CH
2
+XCH═CH
2
→XCH═CHX+YCH═CH
2
→XCH═CHY.
Dimerization of one of the initial terminal olefins unexpectedly results in faster rates of reaction, enhanced trans selectivity, and improved product yield.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A typical reaction scheme for cross metathesis of two terminal olefins is as follows:
XCH═CH
2
+YCH═CH
2
→XCH═CHY
wherein X and Y are independently an alkyl or aryl optionally substituted with one or more alkyl or aryl substitutent groups. X and Y may also optionally include one or more functional groups. Illustrative examples of suitable functional groups include but are not limited to: hydroxyl, thiol, thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, and halogen.
It has been unexpectedly discovered that dimerizing one of the initial terminal olefins results in faster rates of reaction, enhanced trans selectivity, and improved product yield. Dimerization to form a disubstituted olefin intermediate was inspired by the synthesis of telechelic polymers via ring opening polymerization/cross metathesis reaction as shown below.
The present invention is a variation of this theme to make a disubstituted internal olefin product from a first terminal olefin and a second terminal olefin. As an initial matter, the first terminal olefin is reacted with itself to form a dimer. The dimer is then reacted with the second olefin to yield the disubstituted internal olefin product. A schematic illustration of this concept is as follows:
XCH═CH
2
+XCH═CH
2
→XCH═CHX+YCH═CH
2
→XCH═CHY.
Any suitable metathesis catalyst may be used. Illustrative examples of suitable catalysts include ruthenium and osmium carbene catalysts as disclosed by U.S. Pat. Nos.: 5,342,909; 5,312,940; 5,728,917; 5,750,815; 5,710,298, 5831,108, and 5,728,785, all of which are incorporated herein by reference. Briefly, the ruthenium and osmium carbene catalysts possess metal centers that are formally in the +2 oxidation state, have an electron count of 16,are penta-coordinated, and are of the general formula
wherein:
M is ruthenium or osmium;
X and X
1
are each independently any anionic ligand;
L and L
1
are each independently any neutral electron donor ligand;
R and R
1
are each independently hydrogen or a substitutent selected from the group consisting of C
1
-C
20
alkyl, C
2
-C
20
alkenyl, C
2
-C
20
alkynyl, aryl, C
1
-C
20
carboxylate, C
1
-C
20
alkoxy, C
2
-C
20
alkenyloxy, C
2
-C
20
alkynyloxy, aryloxy, C
2
-C
20
alkoxycarbonyl, C
1
-C
20
alkylthio, C
1
-C
20
alkylsulfonyl and C
1
-C
20
alkylsulfinyl. Optionally, each of the R or R
1
substitutent group may be substituted with one or more moieties selected from the group consisting of C
1
-C
10
alkyl, C
1
-C
10
alkoxy, and aryl which in turn may each be further substituted with one or more groups selected from a halogen, a C
1
-C
5
alkyl, C
1
-C
5
alkoxy, and phenyl. Moreover, any of the catalyst ligands may further include one or more finctional groups. Examples of suitable functional groups include but are not limited to: hydroxyl, thiol, thioether, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, and halogen.
In preferred embodiments of these catalysts, the R substitutent is hydrogen and the R
1
substitutent is selected from the group consisting C
1
-C
20
alkyl, C
2
-C
20
alkenyl, and aryl. In even more preferred embodiments, the R
1
substitutent is phenyl or vinyl, optionally substituted with one or more moieties selected from the group consisting of C
1
-C
5
alkyl, C
1
-C
5
alkoxy, phenyl, and a functional group. In especially preferred embodiments, R
1
is phenyl or vinyl substituted with one or more moieties selected from the group consisting of chloride, bromide, iodide, fluoride, —NO
2
, —NMe
2
, methyl, methoxy and phenyl. In the most preferred embodiments, the R
1
substitutent is phenyl.
In preferred embodiments of these catalysts, L and L
1
are each independently selected from the group consisting of phosphine, sulfonated phosphine, phosphite, phosphinite, phosphonite, arsine, stibine, ether, amine, amide, imine, sulfoxide, carboxyl, nitrosyl, pyridine, and thioether. In more preferred embodiments, L and L
1
are each a phosphine of the formula PR
3
R
4
R
5
, where R
3
, R
4
, and R
5
are each independently aryl or C
1
-C
10
alkyl, particularly primary alkyl, secondary alkyl or cycloalkyl. In the most preferred embodiments, L and L
1
ligands are each selected from the group consisting of -P(cyclohexyl)
3
, -P(cyclopentyl)
3
, -P(isopropyl)
3
, and -P(phenyl)
3
.
In preferred embodiments of these catalysts, X and X
1
are each independently hydrogen, halide, or one of the following groups: C
1
-C
20
alkyl, aryl, C
1
-C
20
alkoxide, aryloxide, C
3
-C
20
alkyldiketonate, aryldiketonate, C
1
-C
20
carboxylate, arylsulfonate, C
1
-C
20
alkylsulfonate, C
1
-C
20
alkylthio, C
1
-C
20
alkylsulfonyl, or C
1
-C
20
alkylsulfinyl. Optionally, X and X
1
may be substituted with one or more moieties selected from the group consisting of C
1
-C
10
alkyl, C
1
-C
10
alkoxy, and aryl which in turn may each be further substituted with one or more groups selected from halogen, C
1
-C
5
alkyl, C
1
-C
5
alkoxy, and phenyl. In more preferred embodiments, X and X
1
are halide, benzoate, C
1
-C
5
carboxylate, C
1
-C
5
alkyl, phenoxy, C
1
-C
5
alkoxy, C
1
-C
5
alkylthio, aryl, and C
1
C
5
alkyl sulfonate. In even more preferred embodiments, X and X
1
are each halide, CF
3
CO
2
, CH
3
CO
2
, CFH
2
CO
2
, (CH
3
)
3
CO, (CF
3
)(CH
3
)
2
CO, PhO, MeO, EtO, tosylate, mesylate, or trifluoromethanesulfonate. In the most preferred embodiments, X and X
1
are each chloride.
For the purposes of clarity, the specific details of the present invention will be illustrated with reference to especially preferred embodiments. However, it should be appreciated that these embodiments and examples are for the purposes of illustration only and are not intended to limit the scope of the present invention.
A particularly useful application for the inventive method is in the homologation of terminal alkenes. The terminal alkene may be hindered or unhindered. As shown by Table 1, treatment of a terminal olefin such

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