Cross-metathesis reaction of functionalized and substituted olefins using group 8 transition metal carbene complexes as metathesis catalysts
The invention pertains to the use of Group 8 transition metal carbene complexes as catalysts for olefin cross-metathesis reactions. In particular, ruthenium and osmium alkylidene complexes substituted with an N-heterocyclic carbene ligand are used to catalyze cross-metathesis reactions to provide a variety of substituted and functionalized olefins, including phosphonate-substituted olefins, directly halogenated olefins, 1,1,2-trisubstituted olefins, and quaternary allylic olefins. The invention further provides a method for creating functional diversity using the aforementioned complexes to catalyze cross-metathesis reactions of a first olefinic reactant, which may or may not be substituted with a functional group, with each of a plurality of different olefinic reactants, which may or may not be substituted with functional groups, to give a plurality of structurally distinct olefinic products. The methodology of the invention is also useful in facilitating the stereoselective synthesis of 1,2-disubstituted olefins in the cis configuration.
1. A method for synthesizing a functionalized olefin via a cross-metathesis reaction, comprising contacting (a) a first olefinic reactant with (b) a second olefinic reactant in the presence of (c) a catalyst composed of a Group 8 transition metal alkylidene complex under conditions and for a time period effective to allow cross-metathesis to occur, wherein the catalyst has the structure of formula (VIC)
in which:
M is Ru;
X 1 and X 2 are independently selected from the group consisting of halide, CF 3 CO 2 , CH 3 CO 2 , CFH 2 CO 2 , (CH 3 ) 3 CO, (CF 3 ) 2 (CH 3 )CO, (CF 3 )(CH 3 ) 2 CO, PhO, MeO, EtO, tosylate, mesylate, and trifluoromethanesulfonate;
R 1 is hydrogen and R 2 is selected from the group consisting of C 1 -C 20 alkyl, C 2 -C 20 alkenyl, and aryl;
L is a neutral electron donor ligand selected from the group consisting of phosphine, phosphite, phosphinite, phosphonite, ether, amine, amide, imine, carboxyl, pyridine, substituted pyridine, imidazole, and substituted imidazole;
R 3 and R 4 are aromatic, substituted aromatic, heteroaromatic, substituted heteroaromatic, alicyclic, substituted alicyclic, heteroatom-containing alicyclic, or substituted heteroatom-containing alicyclic, composed of from one to about five rings; and
R 22 and R 23 , are hydrogen, and R 22A and R 23A are selected from hydrogen, lower alkyl and phenyl, or are linked to form a cyclic group; and
wherein any two or more of X 1 , X 2 , L, R 1 , R 2 , R 3 , and R 4 can be taken together to form a chelating multidentate ligand;
wherein the first olefinic reactant has the structure of formula (VIII)
wherein:
R 5 , R 6 and R 7 are independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, substituted heteroatom-containing hydrocarbyl, and —(Z) n ,-Fn,
where n is zero or 1;
Z is selected from the group consisting of hydrocarbylene and substituted hydrocarbylene linking group; and
Fn is a functional group selected from phosphonato;
wherein the second olefinic reactant has the molecular structure R 18 R 19 C═CR 20 R 21 , wherein R 18 , R 19 , R 20 , and R 21 are independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl.
2. The method of claim 1 , wherein:
R 1 is hydrogen, and R 2 is phenyl, vinyl, methyl, isopropyl, or t-butyl, optionally substituted with one or more moieties selected from the group consisting of C 1 -C 6 alkyl, C 1 -C 6 alkoxy, phenyl, and a functional group Fn; and
L is a phosphine of the formula PR 27 R 28 R 29 , where R 27 , R 28 , and R 29 are each independently aryl or C 1 -C 10 alkyl.
3. The method of claim 2 , wherein:
L is selected from the group consisting of —P(cyclohexyl) 3 , —P(cyclopentyl) 3 , —P(isopropyl) 3 , —P(phenyl) 3 , —P(phenyl) 2 (R 7 ) and —P(phenyl)(R 7 ) 2 , in which R 7 is lower alkyl; and
R 3 and R 4 are the same and are either aromatic or C 7 -C 12 alicyclic, if aromatic, each having the structure of formula (XI)
in which R 24 , R 25 , and R 26 are each independently hydrogen, C 1 -C 10 alkyl, C 1 -C 10 alkoxy, aryl, substituted aryl, halogen, or a functional group.
4. The method of claim 3 , wherein:
X 1 and X 2 are halide;
R 2 is phenyl or —CH═C(CH 3 ) 2 ;
R 3 and R 4 are mesityl, diisopinocamphenyl, or 2,4,2′,6′-tetramethylbiphenylyl;
L is selected from the group consisting of —P(cyclohexyl) 3 and —P(cyclopentyl) 3 ; and
R 22 and R 23 are hydrogen.
5. The method of claim 1 , wherein R 5 , R 6 and R 7 are hydrogen, n is zero, and Fn is phosphonato, such that the first olefinic reactant is a vinylphosphonate having the structure of formula (XII)
wherein R 27 and R 28 are hydrocarbyl.
6. The method of claim 1 , wherein for the first olefinic reactant, R 5 , R 6 and R 7 are hydrogen, n is 1, and Fn is selected from the group consisting of phosphonato.
7. The method of claim 6 , wherein Fn is phosphonato, such that the first olefinic reactant is an allylphosphonate having the structure of formula (XIII)
wherein R 27 and R 28 are hydrocarbyl.
8. The method of claim 1 , wherein the catalyst is selected from