Ludger A. Wessjohann

Synthesis of natural-product-based compound libraries

Natural products cover a diversity space not yet available from synthetic libraries, with an unrivalled success rate as drug leads. The combinatorial synthesis of non-oligomeric natural-product-based libraries, however, is still limited to few examples because access to easily modified units strongly depends on the availability of a core structure either from a natural source, or through a suitable synthetic route. Only a few resourceful groups have managed the latter approach for more demanding multifunctional natural drug leads, such as epothilones.

New C2-symmetric chiral disulfide ligands derived from (R)-cysteine

Abstract Several sulfur-containing optically active C 2 -symmetrical ligands have been synthesized from ( R )-cysteine and applied successfully as chiral catalysts in the asymmetric addition of diethylzinc to aldehydes. The resulting secondary alcohols could be obtained in good yields and excellent enantiomeric excess.

R,R‐(+)‐Bis­[(3‐benzyl­oxazolan‐4‐yl)­methyl] di­sulfide

R,R-Bisxad[(3-benzylxadoxazolan-4-yl)-methyl] dixadsulfide, C22H28N2O2S2, is a chiral dixadsulfide which is a highly effective catalyst for the enantioselective addition of diethylxadzinc to aldehydes, including aliphatic ones. The molxadecule has crystallographic twofold rotation symmetry.