Patents by Inventor Kam To Wan

Kam To Wan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6232494
    Abstract: This invention is directed to an improved process for the preparation of N-(phosphonomethyl)glycine (i.e., “glyphosate”), a salt of N-(phosphonomethyl)glycine, or an ester of N-(phosphonomethyl)glycine. The process comprises combining an N-substituted N-(phosphonomethyl)glycine reactant with oxygen in the presence of a noble metal catalyst. The N-substituted N-(phosphonomethyl)glycine reactant has formula (V): wherein R1 and R2 are independently selected from the group consisting of hydrogen, halogen, —PO3R12R131, —SO3R14, —NO2, hydrocarbyl, and substituted hydrocarbyl other than —CO2R15; and R7, R8, R9, R12, R13, R14, and R15 are independently selected from the group consisting of hydrogen, hydrocarbyl, substituted hydrocarbyl, and an agronomically acceptable cation.
    Type: Grant
    Filed: March 5, 1999
    Date of Patent: May 15, 2001
    Assignee: Monsanto Company
    Inventors: David A. Morgenstern, David E. McKenzie, Robert Orth, David Oburn, Cindy Ludwig, Kam-to Wan, John M. Dzenitis
  • Patent number: 6184413
    Abstract: Supported phase catalysts in which the support phase is highly polar, most preferably ethylene glycol or glycerol, are disclosed. An organometallic compound, preferably a metal complex of chiral sulfonated 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl is dissolved in the support phase. Such supported phase catalysts are useful for asymmetric synthesis of optically active compounds, including the asymmetric hydrogenation of prochiral unsaturated carbon-hetero atom bonds, such as ketones, imines and beta-keto esters.
    Type: Grant
    Filed: June 11, 1999
    Date of Patent: February 6, 2001
    Assignee: California Institute of Technology
    Inventors: Mark E. Davis, Kam To Wan
  • Patent number: 5935892
    Abstract: Supported phase catalysts in which the support phase is highly polar, most preferably ethylene glycol or glycerol, are disclosed. An organometallic compound, preferably a metal complex of chiral sulfonated 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP) is dissolved in the support phase. Such supported phase catalysts are useful for asymmetric synthesis of optically active compounds, including the asymmetric hydrogenation of prochiral unsaturated carbon-hetero atom bonds, such as ketones, imines and beta-keto esters. The phenyl groups of the BINAP ligand are at least meno-sulfonated and the ligand overall is terra- to hexa-sulfonated. Ruthemium is the perferred metal.
    Type: Grant
    Filed: April 10, 1997
    Date of Patent: August 10, 1999
    Assignee: California Institute of Technology
    Inventors: Mark E. Davis, Kam To Wan
  • Patent number: 5827794
    Abstract: The present invention relates to water soluble chiral sulfonated 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl and its use as organometallic catalysts for asymmetric synthesis of optically active compounds. Asymmetric reactions of the present invention include those reactions in which organometallic catalysts are commonly used. Such reactions include, but are not limited to, reduction and isomerization reactions on unsaturated substrates and carbon--carbon bond forming reactions. Examples of such reactions include, but are not limited to, hydrogenation, hydroboration, hydrosilylation, hydride reduction, hydroformylation, alkylation, allylic alkylation, arylation, alkenylation, epoxidation, hydrocyanation, disilylation, cyclization and isomerization reactions.The catalysts of the present invention provide the advantage of functioning in the presence of water without loss in enantioselectivity relative to the nonsulfonated BINAP catalyst in an organic solvent.
    Type: Grant
    Filed: September 28, 1995
    Date of Patent: October 27, 1998
    Assignee: California Institute of Technology
    Inventors: Mark E. Davis, Kam To Wan
  • Patent number: 5756838
    Abstract: The present invention relates to water soluble chiral sulfonated 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl and its use as organometallic catalysts for asymmetric synthesis of optically active compounds. Asymmetric reactions of the present invention include those reactions in which organometallic catalysts are commonly used. Such reactions include, but are not limited to, reduction and isomerization reactions on unsaturated substrates and carbon--carbon bond forming reactions. Examples of such reactions include, but are not limited to, hydrogenation, hydroboration, hydrosilylation, hydride reduction, hydroformylation, alkylation, allylic alkylation, arylation, alkenylation, epoxidation, hydrocyanation, disilylation, cyclization and isomerization reactions.The catalysts of the present invention provide the advantage of functioning in the presence of water without loss in enantioselectivity relative to the nonsulfonated BINAP catalyst in an organic solvent.
    Type: Grant
    Filed: August 16, 1995
    Date of Patent: May 26, 1998
    Assignee: California Institute of Technology
    Inventors: Mark E. Davis, Kam To Wan
  • Patent number: 5736480
    Abstract: Supported phase catalysts in which the support phase, is non-aqueous and highly polar, such as a primary alcohol, and most preferably ethylene glycol, are. disclosed. An organometallic compound, preferably a metal complex of chiral sulfonated 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl is dissolved in the ethylene glycol. Such supported phase catalysts are useful for asymmetric synthesis of optically active compounds, such as the preparation of dehydronaproxen.
    Type: Grant
    Filed: January 12, 1995
    Date of Patent: April 7, 1998
    Assignee: California Institute of Technology
    Inventors: Mark E. Davis, Kam To Wan