Expanding the scope of asymmetric electrophilic atom-transfer reactions: titanium- and ruthenium-catalyzed hydroxylation of beta-ketoesters.

ABSTRACT: The enantioselective formation of a quaternary stereogenic center coinciding with a hydroxylation process is a very rare reaction from a homogeneous catalysis point of view. Indeed, to our knowledge, no asymmetric transition-metal-catalyzed direct hydroxylation has been reported before. We describe here our initial study concerning the enantioselective alpha-hydroxylation of various beta-ketoesters catalyzed by Lewis-acidic complexes. Specifically, it was found that the Ti complex [TiCl(2)((R,R)-1-Np-TADDOLato)(MeCN)(2)] affords the hydroxylated products in high yield and enantioselectivities up to 94% enantiomeric excess when using 2-(phenylsulphonyl)-3-(4-nitrophenyl)oxaziridine as the oxidizing agent. Chiral enantiopure compounds of the latter type have been used previously in stoichiom

SUBMITTER: Toullec PY 

PROVIDER: S-EPMC395990 | biostudies-literature | 2004 Apr

REPOSITORIES: biostudies-literature