Building up quarternary stereocenters of chromans by asymmetric redox organocatalysis: a new entry to vitamin E.
High-turnover catalysis offers a novel concept for the efficient chemo- and enantioselective preparation of chroman intermediates, which are useful for the synthesis of tocopherols (vitamin E components) and other biologically active compounds. A chiral ammonium iodide catalyst mediates the cycloetherification in combination with a cooxidant and an inorganic base in excellent yield and up to 93 % ee. OTs=para-toluenesulfonyl.
Research and Development, DSM Nutritional Products, P.O. Box 2676, 4002 Basel (Switzerland). thomas.netscher@dsm.com.
Thomas
T
Netscher
D064751:Ammonium Compounds; D002384:Catalysis; D002839:Chromans / Q000737:chemistry*; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013237:Stereoisomerism; D014105:Tosyl Compounds / Q000737:chemistry; D014810:Vitamin E / Q000138:chemical synthesis / Q000737:chemistry*
D064751:Ammonium Compounds; D002839:Chromans; D000644:Quaternary Ammonium Compounds; D014105:Tosyl Compounds; D014810:Vitamin E; C582942:ammonium iodide
antioxidants; asymmetric catalysis; biological activity; tocopherols; tocotrienols