Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-12-21
2003-02-04
Nazario-Gonzalez, Porfirio (Department: 1621)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S091000, C526S092000, C526S093000, C526S171000, C526S172000, C526S183000, C526S282000, C526S283000, C502S152000, C502S162000, C556S021000, C556S136000, C556S137000
Reexamination Certificate
active
06515084
ABSTRACT:
BACKGROUND
This invention relates to highly active and stable ruthenium and osmium metal carbene complex compounds, their synthesis and use as catalysts for olefin metathesis reactions.
Transition-metal catalyzed C—C bond formation via olefin metathesis is of considerable interest and synthetic utility. Initial studies in this area were based on catalytically active mixtures consisting of transition-metal chlorides, oxides or oxychlorides, cocatalysts such as EtAlCl
2
or R
4
Sn, and promoters including O
2
, EtOH or PhOH. For example, WCl
6
/EtAlCl
2
/EtOH 1:4:1. These systems catalyze olefin metathesis reactions, however their catalytic centers are ill-defined and systematic control of their catalytic activity is not possible.
Recent efforts have been directed towards the development of well-defined metathesis active catalysts based on transition metal complexes. The results of research efforts during the past two decades have enabled an in-depth understanding of the olefin metathesis reaction as catalyzed by early transition metal complexes. In contrast, the nature of the intermediates and the reaction mechanism for Group VIII transition metal catalysts have remained elusive. In particular, the oxidation states and ligation of the ruthenium and osmium metathesis intermediates are not known.
Group VIII transition metal olefin metathesis catalysts, specifically ruthenium and osmium carbene complexes, have been described in U.S. Pat. Nos. 5,312,940 and 5,342,909 and U.S. patent application Ser. Nos. 08/282,826 and 08/282,827, all of which are incorporated herein by reference. The ruthenium and osmium carbene complexes disclosed in these patents and applications are of the general formula
where M is ruthenium or osmium, X and X
1
are anionic ligands, and L and L
1
are neutral electron donors. U.S. Pat. Nos. 5,312,940 and 5,342,909 disclose specific vinyl alkylidene ruthenium and osmium complexes and their use in catalyzing the ring opening metathesis polymerization (“ROMP”) of strained olefins. In all of the specific alkylidene complexes disclosed in these patents, R
1
is hydrogen and R is either a substituted or unsubstituted vinyl group. For example, a preferred vinyl alkylidene complex disclosed in these patents is
where Ph is phenyl.
U.S. patent application Ser. Nos. 08/282,826 and 08/282,827 disclose specific vinyl alkylidene ruthenium and osmium complexes and their use in catalyzing a variety of metathesis reactions. The catalysts disclosed in these applications have specific neutral electron donor ligands L and L
1
; namely, phosphines in which at least one substituent is a secondary-alkyl or cycloalkyl group. As in the above U.S. patents, in all of the specific alkylidene complexes disclosed in the patent applications, R
1
is hydrogen and R is either a substituted or unsubstituted vinyl group. For example, a preferred vinyl alkylidene complex disclosed in these patent applications is
where Cy is cyclohexyl.
Although the vinyl alkylidene complexes disclosed in the above patents and patent applications exhibit high metathesis activity and remarkable stability towards functional groups there are at least two drawbacks to these complexes as metathesis catalysts. First, the preparation of the vinyl alkylidene complexes requires a multi-step synthesis; and second, the vinyl alkylidene complexes have relatively low initiation rates. Both of these aspects of the vinyl alkylidene complexes are undesirable for their use as metathesis catalysts. The multi-step synthesis may be time consuming and expensive and may result in lower product yields. The low initiation rate may result in ROMP polymers with a broad molecular weight distribution and prolonged reaction times in ring closing metathesis (“RCM”) reactions.
For the reasons discussed above, there is a need for well-defined metathesis active catalysts that have the following characteristics: first, they are stable in the presence of a wide variety of functional groups; second, they can catalyze a variety of metathesis reactions including the metathesis of acyclic and unstrained cyclic olefins; third, they have a high initiation rate; and fourth, they are easily prepared. Furthermore, there is a need for olefin metathesis catalysts that can catalyze the ROMP of strained and unstrained cyclic olefins to yield polymers of very low polydispersity (i.e., PDI≈1.0) and that can catalyze the RCM of acyclic dienes with short reaction times.
SUMMARY
The present invention meets the above needs and provides well-defined ruthenium and osmium carbene compounds that are stable in the presence of a variety of functional groups and can be used to catalyze olefin metathesis reactions on unstrained cyclic and acyclic olefins. The compounds of the present invention are highly active in metathesis reactions and have high initiation rates.
In one embodiment of the present invention, the ruthenium and osmium carbene compounds have the formula
where M may be Os or Ru; R
1
is hydrogen; X and X
1
may be different or the same and are any anionic ligand; L and L
1
may be different or the same and are any neutral electron donor; and R may be hydrogen, substituted or unsubstituted alkyl, or substituted or unsubstituted aryl.
The ruthenium and osmium carbene complexes of the present invention are stable in the presence of a variety of functional groups. A consequence of this is that the alkyl and aryl R group may contain one or more functional groups including alcohol, thiol, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, and halogen groups.
R is preferably hydrogen, C
1
-
20
alkyl, or aryl. The C
1
-
20
alkyl may optionally be substituted with one or more aryl, halide, hydroxy, C
1
-
20
alkoxy, or C
2
-
20
alkoxycarbonyl groups. The aryl may optionally be substituted with one or more C
1
-
20
alkyl, aryl, hydroxyl, C
1
-
5
alkoxy, amino, nitro, or halide groups.
L and L
1
are preferably phosphines of the formula PR
3
R
4
R
5
, where R
3
is a secondary alkyl or cycloalkyl, and R
4
and R
5
are aryl, C
1
-
10
primary alkyl, secondary alkyl, or cycloalkyl. R
4
and R
5
may be the same or different.
L and L
1
are are most preferably the same and are —P(cyclohexyl)
3
, —P(cyclopentyl)
3
, or —P(isopropyl)
3
.
X and X
1
are most preferably the same and are chlorine.
In another embodiment of the present invention, the ruthenium and osmium carbene compounds have the formula
where M may be Os or Ru; X and X
1
may be different or the same and are any anionic ligand; L and L
1
may be different or the same and are any neutral electron donor; and R
9
and R
10
may be different or the same and may be hydrogen, substituted or unsubstituted alkyl, or substituted or unsubstituted aryl. The R
9
and R
10
groups may optionally include one or more of the following functional groups: alcohol, thiol, ketone, aldehyde, ester, ether, amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, and halogen groups
The ruthenium and osmium carbene compounds of the present invention may be used to catalyze olefin metathesis reactions including, but not limited to, ROMP, RCM, depolymerization of unsaturated polymers, synthesis of telechelic polymers, and olefin synthesis.
In the ROMP reaction, a compound according to the present invention is contacted with a cyclic olefin to yield a ROMP polymer product. In the RCM reaction, a compound according to the present invention is contacted with a diene to yield a ring-closed product. In the depolymerization reaction, a compound according to the present invention is contacted with an unsaturated polymer in the presence of an acyclic olefin to yield a depolymerized product. In the synthesis of telechelic polymers, a compound according to the present invention is contacted with a cyclic olefin in the presence of an &agr;,&ohgr;-difunctional olefin to yield a telechelic polymer. In the olefin synthesis reaction, a compound according to the present invention is contacted with one or
Grubbs Robert H.
Nguyen Sonbinh T.
Schwab Peter
California Institute of Technology
Nazario-Gonzalez Porfirio
Pillsbury & Winthrop LLP
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