Organocatalytic Asymmetric Synthesis of Dihydroisoquinolinones via a One-Pot Aza-Henry-Hemiaminalization-Oxidation Sequence

Traceless Redox-Annulations of Alicyclic Amines

Amines such as 1,2,3,4-tetrahydroisoquinoline undergo redox-neutral annulations with ortho-(nitromethyl)benzaldehyde. Benzoic acid acts as a promoter in these reactions, which involve concurrent amine α-C-H bond and N-H bond functionalization. Subsequent removal of the nitro group provides access to tetrahydroprotoberberines not accessible via typical redox-annulations. Also reported are decarboxylative annulations of ortho-(nitromethyl)benzaldehyde with proline and pipecolic acid.

Development of a Cross-Conjugated Vinylogous [4+2] Anionic Annulation and Application to the Total Synthesis of Natural Antibiotic (±)-ABX

The cross‐conjugated vinylogous [4+2] anionic annulation has been newly developed, the cascade process of which has a high preference for regiochemical control and chemoselectivity, giving rise to exclusively Michael‐type adducts in moderate to high yields (up to 94 %, 35 examples). By making use of this approach as a key operation, the first total synthesis of natural antibiotic ABX, in racemic form, has been successfully achieved in a concise 7‐step sequence with an overall yield of about 20 %.