Enantioselective, Biocatalytic Reduction of 3-Substituted Cyclopentenones: Application to the Asymmetric Synthesis of an hNK-1 Receptor Antagonist

From racemic precursors to fully stereocontrolled products: one-pot synthesis of chiral α-amino lactones and lactams

Substituted racemic lactols or cyclic hemiaminals were directly used as nucleophiles in enamine-based asymmetric amination reactions to access enantioenriched α-amino lactones or lactams via a one-pot sequence. The desired products, which are very important building blocks in organic synthesis but difficult to be prepared in the optically enriched form, could be afforded with two stereogenic centers in high yields with excellent enantioselectivities. Moreover, starting from the racemic precursors and catalyzed by the enantiomeric pair of the catalyst, all possible stereoisomeric products were discretely provided only after simple column chromatography. Additionally, this protocol provides facile access to several novel bicyclic carbamates, and such drug-like heterocyclic compounds should be potentially useful in medicinal chemistry.

Highly enantioselective catalytic 1,3-dipolar cycloadditions of α-alkyl diazoacetates: efficient synthesis of functionalized 2-pyrazolines

Chiral oxazaborolidinium ion catalyzed 1,3-dipolar cycloaddition reaction of α-substituted diazoacetates gives functionalized 2-pyrazolines in high to excellent enantiomeric ratios.