Stereoselective Synthesis of Chiral ?-SCF3-?-Ketoesters Featuring a Quaternary Stereocenter

Stereoselective Reduction of b-Hydroxy a-Ketoesters: A Concise Synthesis of anti-a,b-Dihydroxy Esters Stereoselective Reduction of b-Hydroxy a-Ketoesters

Total synthesis of LFA-1 antagonist BIRT-377 via organocatalytic asymmetric construction of a quaternary stereocenter.

A catalytic route for enantioselective total synthesis of cell adhesion inhibitor BIRT-377 is described. The quaternary stereocenter was constructed through l-proline-derived, tetrazole-catalyzed direct asymmetric alpha-amination of 3-(4-bromophenyl)-2-methylpropanal with dibenzyl azodicarboxylate. In the course of these studies, a one-pot trifluoro acetylation/selective benzyloxycarbonyl depro...

Palladium-catalyzed asymmetric synthesis of 2-pyrrolidinones with a quaternary carbon stereocenter.

A palladium-catalyzed asymmetric synthesis of 2-pyrrolidinones with a quaternary stereocenter at the 3-position has been achieved by the reaction of γ-methylidene-δ-valerolactones with alkyl isocyanates. High enantioselectivity has been realized by employing a newly synthesized chiral phosphoramidite ligand.

Stereoselective amine-thiourea-catalysed sulfa-Michael/nitroaldol cascade approach to 3,4,5-substituted tetrahydrothiophenes bearing a quaternary stereocenter

An investigation on the stereoselective cascade sulfa-Michael/aldol reaction of nitroalkenes and commercially available 1,4-dithiane-2,5-diol to 3,4,5-substituted tetrahydrothiophenes, bearing a quaternary stereocenter, is presented. A secondary amine thiourea derived from (R,R)-1,2-diphenylethylamine was found to be the most effective catalyst when using trans-β-methyl-β-nitrostyrenes affordin...

Stereoselective synthesis of a topologically chiral molecule: the trefoil knot.

Topological chirality of a molecule is realized when any representation of its graph is topologically distinct from its mirror image, i.e. if it can not be converted to its mirror image by continuous deformation in 3D-space. [1] This property implies that the graph of the molecule is non-planar. Molecular systems with an intrinsically non-planar graph are scare. Their graphs can be contracted t...