摘要:
Catalytic complexes including a metal atom having anionic ligands, at least one nucleophilic carbene ligand, and an alkylidene, vinylidene, or allenylidene ligand. The complexes are highly stable to air, moisture and thermal degradation. The complexes are designed to efficiently carry out a variety of olefin metathesis reactions.
摘要:
Catalytic complexes including a metal atom having anionic ligands, at least one nucleophilic carbine ligand, and an alkylidene, vinylidene, or allenylidene ligand. The complexes are highly stable to air, moisture and thermal degradation. The complexes are designed to efficiently carry out a variety of olefin metathesis reactions.
摘要:
Catalytic complexes including a metal atom having anionic ligands, at least one nucleophilic carbine ligand, and an alkylidene, vinylidene, or allenylidene ligand. The complexes are highly stable to air, moisture and thermal degradation. The complexes are designed to efficiently carry out a variety of olefin metathesis reactions.
摘要:
This invention provides a process for conducting amination reactions. The processes of the present invention make use of N-heterocyclic carbenes as ancillary ligands in aminations of aryl halides and aryl pseudohalides. An amination can be carried out by mixing, in a liquid medium, at least one strong base; at least one aryl halide or aryl pseudohalide in which all substituents are other than amino groups, wherein the aryl halide has, directly bonded to the aromatic ring(s), at least one halogen atom selected from the group consisting of a chlorine atom, a bromine atom, and an iodine atom; at least one primary amine and/or at least one secondary amine; at least one metal compound comprising at least one metal atom selected from nickel, palladium, and platinum, wherein the formal oxidation state of the metal is zero or two; and at least one N-heterocyclic carbene. One preferred type of N-heterocyclic carbene is an imidazoline-2-ylidene of the formula wherein R1 and R2 are each, independently, alkyl or aryl groups having at least 3 carbon atoms, R3 and R4 are each, independently, a hydrogen atom, a halogen atom, or a hydrocarbyl group.
摘要:
This invention provides a process for conducting Suzuki coupling reactions. The processes of the present invention make use of N-heterocyclic carbenes as ancillary ligands in Suzuki couplings of aryl halides and aryl pseudohalides. A Suzuki coupling can be carried out by mixing, in a liquid medium, at least one strong base; at least one aryl halide or aryl pseudohalide in which all substituents are other than boronic acid groups, wherein the aryl halide has, directly bonded to the aromatic ring(s), at least one halogen atom selected from the group consisting of a chlorine atom, a bromine atom, and an iodine atom; at least one arylboronic acid in which all substituents are other than chlorine atoms, bromine atoms, iodine atoms, or pseudohalide groups; at least one metal compound comprising at least one metal atom selected from nickel, palladium, and platinum, wherein the formal oxidation state of the metal is zero or two; and at least one N-heterocyclic carbene. One preferred type of N-heterocyclic carbene is an imidazoline-2-ylidene of the formula wherein R1 and R2 are each, independently, alkyl or aryl groups having at least 3 carbon atoms, R3 and R4 are each, independently, a hydrogen atom, a halogen atom, or a hydrocarbyl group.
摘要:
This invention provides a process for conducting Kumada coupling reactions. The processes of the present invention make use of N-heterocyclic carbenes as ancillary ligands in Kumada couplings of aryl halides. A Kumada coupling can be carried out by mixing, in a liquid medium, at least one aryl halide, wherein the aryl halide has, directly bonded to the aromatic ring(s), at least one halogen atom selected from the group consisting of a chlorine atom, a bromine atom, and an iodine atom; at least one Grignard reagent; at least one metal compound comprising at least one metal atom selected from nickel, palladium, and platinum, wherein the formal oxidation state of the metal is zero or two; and at least one N-heterocyclic carbene. One preferred type of N-heterocyclic carbene is an imidazoline-2-ylidene of the formula wherein R1 and R2 are each, independently, alkyl or aryl groups having at least 3 carbon atoms, R3 and R4 are each, independently, a hydrogen atom, a halogen atom, or a hydrocarbyl group. Homocoupling of aryl pseudohalides is also feasible using the processes of this invention.
摘要:
Catalytic complexes including a metal atom having anionic ligands, at least one nucleophilic carbene ligand, and an alkylidene, vinylidene, or allenylidene ligand. The complexes are highly stable to air, moisture and thermal degradation. The complexes are designed to efficiently carry out a variety of olefin metathesis reactions.
摘要:
Catalytic complexes including a metal atom having anionic ligands, at least one nucleophilic carbine ligand, and an alkylidene, vinylidene, or allenylidene ligand. The complexes are highly stable to air, moisture and thermal degradation. The complexes are designed to efficiently carry out a variety of olefin metathesis reactions.
摘要:
This invention provides a process for conducting Stille coupling reactions. The processes of the present invention make use of N-heterocyclic carbenes as ancillary ligands in Stille couplings of aryl halides. A Stille coupling can be carried out by mixing, in a liquid medium, at least one strong base; at least one aryl halide or aryl pseudohalide in which all substituents are other than stannyl groups, wherein the aryl halide has, directly bonded to the aromatic ring(s), at least one halogen atom selected from the group consisting of a chlorine atom, a bromine atom, and an iodine atom; at least one organotin compound wherein the tin atom is quaternary, wherein one group bound to the tin atom is unsaturated at the alpha or beta position, and wherein each of the remaining groups bound to the tin atom is a saturated group; at least one metal compound comprising at least one metal atom selected from nickel, palladium, and platinum, wherein the formal oxidation state of the metal is zero or two; and at least one N-heterocyclic carbene. One preferred type of N-heterocyclic carbene is an imidazoline-2-ylidene of the formula wherein R1 and R2 are each, independently, alkyl or aryl groups having at least 3 carbon atoms, R3 and R4 are each, independently, a hydrogen atom, a halogen atom, or a hydrocarbyl group.
摘要:
This invention provides a catalyst system useful in many coupling reactions, such as Suzuki, Kumada, Heck, and amination reactions. The catalyst system of the present invention makes use of N-heterocyclic carbenes or their protonated salts. The composition of the catalyst system comprises at least one transition metal compound and at least one N-heterocyclic carbene or its protonated salt. This invention further provides novel N-heterocyclic carbenes and their protonated salts. One type of N-heterocyclic carbene used in this invention is an imidazolinc-2-ylidene wherein the 1 and 3 positions are each, independently, substituted by an aromatic group in which each ortho position is, independently, substituted by a secondary or tertiary group which has at least three atoms.