Photochemical Deracemization of Chiral Sulfoxides Catalyzed by a Hydrogen-Bonding Xanthone Sensitizer
作者:Laura Wimberger、Thilo Kratz、Thorsten Bach
DOI:10.1055/s-0039-1690034
日期:2019.12
photochemical behavior was studied in the presence of xanthone and thioxanthone sensitizers. While acyclic sulfoxides showed only decomposition, chiral benzothiazinone-1-oxides with a stereogenic sulfur atom underwent a stereomutation upon irradiation at λ = 366 nm in the presence of catalytic quantities of a xanthone sensitizer. A chiral xanthone with a 1,5,7-trimethyl-3-azabicyclo-[3.3.1]nonan-2-one
Hydrogen bond induced enantioselectivity in Mn(salen)-catalysed sulfoxidaton reactions
作者:Felix Voss、Eberhardt Herdtweck、Thorsten Bach
DOI:10.1039/c0cc04636a
日期:——
A chiral Mn(salen) complex exhibiting two lactam binding sites at two rigid 1,5,7-trimethyl-3-azabicyclo[3.3.1]nonan-2-one skeletons is capable of enantioselective sulfoxidation due to spatially remote substrate hydrogen bonding.
A terminal alkyne was prepared, which is linked by a carbon-carbon bond to a conformationally restricted, U-shaped chiral lactam, that is, more precisely, to carbon atom C7 of 1,5,7-trimethyl-3-azabicyclo[3.3.1]nonan-2-one. The alkyne was connected to various ligands (bipyridine, terpyridine, pybox) by Sonogashira cross-coupling with the respective bromides or triflates. The resulting products were