Central-to-Axial Chirality: Asymmetric Organocatalytic Synthesis of Axially Chiral Chalcones via Exocyclic Dihydronaphthalenes.

Asymmetric synthesis of an unprecedented exocyclic dihydronaphthalene and an axially chiral naphthalene chalcone has been disclosed. Good to excellent asymmetric induction is achieved. The success is attributed to the unusual formation of exocyclic dihydronaphthalene, which plays a crucial role in ensuring axial chirality.

Asymmetric Umpolung (3+2) Cycloadditions of Iminoesters with α,β-Unsaturated-2-acyl Imidazoles for the Synthesis of Substituted Pyrrolidines.

An enantioselective (3+2) cycloaddition reaction of iminoesters occurring with opposite regioselectivity is reported. This reaction provides chiral polysubstituted pyrrolidines with high enantioselectivities (up to 97%), diastereoselectivities (>20:1), and yields (up to 99%). Interestingly, changing the alpha-substituents of the iminoesters from an aryl to an aliphatic (benzyl) group or hydrogen resulted in the formation of normal (3+2) cycloaddition products, also in excellent enantioselectivities.