An asymmetric synthesis of 1,2,4-trioxane anticancer agents via desymmetrization of peroxyquinols through a Brønsted acid catalysis cascade

Recent progress on asymmetric organocatalytic construction of chiral cyclohexenone skeletons

Chiral cyclohex-2-enones are important intermediates in synthetic chemistry as well as in the life science industries. In this focus review, recent advances in the organocatalytic asymmetric synthesis of chiral cyclohex-2-enone skeletons are summarized. The reaction mechanisms are also briefly discussed.

Enantioselective synthesis of benzazepinoindoles bearing trifluoromethylated quaternary stereocenters catalyzed by chiral spirocyclic phosphoric acids

SPA-catalyzed iso-Pictet–Spengler reaction of C-2-linked o-aminobenzylindoles and trifluoromethyl ketones for construction of optically enriched benzazepinoindole derivatives has been realised.

Asymmetric copper(I)-catalyzed azide-alkyne cycloaddition to quaternary oxindoles

We report a highly enantioselective Cu(I)-catalyzed azide-alkyne cycloaddition via asymmetric desymmetrization of oxindole-based 1,6-heptadiynes, which furnishes quaternary oxindoles bearing a 1,2,3-triazole-containing moiety with 84-98% ee.

Enantioselective synthesis of hindered cyclic dialkyl ethers via catalytic oxa-Michael/Michael desymmetrization

An asymmetric oxa-Michael/Michael cascade reaction of p-quinols and α,β-unsaturated aldehydes provides access to hindered dialkyl ethers. A highly enantioselective oxa-Michael addition of a tertiary alcohol precedes an intramolecular cyclohexadienone desymmetrization, which allows for the concomitant formation of four contiguous stereocenters in a single step. The highly functionalized bicyclic frameworks are rapidly obtained from simple starting materials with good diastereoselection and serve as valuable precursors for further manipulation.

Organocatalytic domino reaction of cyanosulfones: access to complex cyclohexane systems with quaternary carbon centers

When ε-nitro-α,β-unsaturated esters are added to conjugated cyanosulfones in the presence of a bifunctional thiourea catalyst, a highly stereoselective domino reaction occurs to generate complex cyclohexanes with up to four stereogenic centers, one of which is quaternary in nature. Therefore, it is demonstrated that, like nitro compounds, sulfones can undergo an asymmetric intramolecular conjugate addition to α,β-unsaturated esters in the presence of a bifunctional organocatalyst.