Synthesis of ansa-metallocenes and their parent ligands in high yield

A method for making (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene, comprising:

• a) contacting 2,7-di-tert-butylfluorene and an alkyl lithium reagent in an ethereal solvent to form a first mixture, wherein the 2,7-di-tert-butylfluorene is substantially deprotonated to form Li(2,7-di-tert-butylfluorenyl);
• b) rapidly combining the ethereal solution of Li(2,7-di-tert-butylfluorenyl) with 6-methyl-6-(3-butenyl)fulvene,
• to form a second mixture, wherein the limiting reagent has substantially reacted;
• and
• c) contacting the second mixture with a proton source to form a third mixture comprising (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene in at least about 85% yield.

A method for making a compound of the formula

• comprising:
• a) contacting a compound of the formula
• and a first alkyl lithium reagent in a first ethereal solvent to form a first mixture, wherein the compound of the formula II is substantially deprotonated to form a lithium salt of compound II, Li(II);
• b) rapidly combining the first mixture with a fulvene compound of the formula
• to form a second mixture, wherein the limiting reagent has substantially reacted;
• c) contacting the second mixture with a proton source to form a third mixture comprising
• including isomers thereof, in at least about 85% yield;
• d) removing the volatile components from the third mixture to provide a residue comprising the compound of the formula I;
• e) optionally triturating the residue with a solvent in which the compound of the formula I is substantially insoluble and the compound of the formula III is soluble to provide the compound of the formula I, followed by isolation of the compound of the formula I;
• f) contacting the compound of the formula I with from about 2 to about 2.5 molar equivalents of a second alkyl lithium reagent in a second ethereal solvent to form a fourth mixture, wherein the compound of the formula I is substantially deprotonated to form a dilithium salt of compound I, Li2(I);
• g) contacting the fourth mixture with M1X4 and an optional hydrocarbon cosolvent to form a fifth mixture comprising
• h) removing the volatile components from the fifth mixture to provide the compound of the formula IV in at least about 80% yield;
• i) optionally washing the compound of the formula IV in a non-polar solvent;
• j) optionally extracting the compound of the formula IV with a polar solvent followed by removing the volatiles from the polar solvent solution to provide the compound of the formula IV;
• and
• k) optionally crystallizing the compound of the formula IV from an aromatic solvent;
• wherein:
• R1 and R2 are independently selected from an aliphatic or substituted aliphatic group having from 1 to about 20 carbon atoms, or hydrogen;
• and
• R3, in each instance, is independently selected from an aliphatic or substituted aliphatic group having from 1 to about 20 carbon atoms, or hydrogen;
• M1 is Zr or Hf;
• and
• X is Cl, Br, or I.

A method for isolating (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene zirconium dichloride, comprising:

• a) contacting 2,7-di-tert-butylfluorene and a first alkyl lithium reagent in a first ethereal solvent to form a first mixture, wherein the 2,7-di-tert-butylfluorene is substantially deprotonated to form Li(2,7-di-tert-butylfluorenyl);
• b) rapidly combining the first ethereal solution of Li(2,7-di-tert-butylfluorenyl) with 6-methyl-6-(3-butenyl)fulvene,
• to form a second mixture, wherein the limiting reagent has substantially reacted;
• c) contacting the second mixture with a proton source to form a third mixture comprising (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene in at least about 85% yield;
• d) removing the volatile components from the third mixture to provide a residue comprising (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene;
• e) optionally triturating the residue with a solvent in which (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex- 1-ene is substantially insoluble and 6-methyl-6-(3-butenyl)fulvene is soluble, and isolating the (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene;
• f) contacting the (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene with from about 2 to about 2.5 molar equivalents of a second alkyl lithium reagent in a second ethereal solvent to form a fourth mixture, wherein the (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene is substantially deprotonated to form Li2(5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene;
• g) contacting the fourth mixture with ZrCl4 and an optional hydrocarbon cosolvent to form a fifth mixture comprising (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene zirconium dichloride;
• h) removing the volatile components from the fifth mixture to provide (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene zirconium dichloride in at least about 80% yield;
• i) optionally washing the (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene zirconium dichloride in a non-polar solvent;
• j) optionally extracting the (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene zirconium dichloride with a polar solvent followed by removing the volatiles from the polar solvent solution to provide (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene zirconium dichloride;
• and
• k) optionally crystallizing the (5-cyclopentadienyl)[5-(2,7-di-tert-butylfluorenyl)]hex-1-ene zirconium dichloride from an aromatic solvent.

A method of making a compound of the formula

• and isomers thereof, comprising:
• a) providing a source of a fluorenyl anion having the formula
• b) rapidly combining the source of the fluorenyl anion with a fulvene compound of the formula
• to form a mixture, wherein either the source of the fluorenyl anion or the compound of the formula III is optionally a limiting reagent, and wherein the limiting reagent, if present, has substantially reacted;
• and
• c) contacting the mixture with a proton source to form and isomers thereof;
• wherein R1 and R2 independently are hydrogen or an aliphatic or substituted aliphatic group having from 1 to about 20 carbon atoms;
• and
• wherein each R3 independently is hydrogen or an aliphatic or substituted aliphatic group having from 1 to about 20 carbon atoms.

A method of making a compound of the formula

• and isomers thereof, comprising:
• a) providing a salt of a fluorenyl anion having the formula
• b) rapidly combining the source of the fluorenyl anion with a fulvene compound of the formula
• to form a mixture, wherein either the source of the fluorenyl anion or the compound of the formula III is optionally a limiting reagent, and wherein the limiting reagent, if present, has substantially reacted;
• and
• c) contacting the mixture with a proton source to form and isomers thereof;
• wherein R1 and R2 independently are hydrogen or an aliphatic or substituted aliphatic group having from 1 to about 20 carbon atoms;
• and
• wherein each R3 independently is hydrogen or an aliphatic or substituted aliphatic group having from 1 to about 20 carbon atoms.