Novel total syntheses of oxoaporphine alkaloids enabled by mild Cu-catalyzed tandem oxidation/aromatization of 1-Bn-DHIQs

Preparation and identification of isoquinoline alkaloids with ATP citrate lyase inhibitory activity from Dactylicapnos scandens

Three new isoquinoline alkaloids including a morphine derivative (1), two aporphine alkaloids (2-3), together with five known alkaloids (4-8) were obtained from the extract of Dactylicapnos scandens (D.Don) Hutch. (D. scandens). Their structures and absolute configurations were elucidated by extensive spectroscopic data analysis including HRESIMS, NMR and electronic circular dichroism (ECD) and ECD calculation. Compounds 1-8 were evaluated for ATP Citrate Lyase (ACLY) inhibitory activity through an enzymatic assay. Among them, 2 and 3 showed the high ACLY inhibitory activity with an IC50 value of 10.48 ± 1.59 and 10.89 ± 4.89 μM.

Copper(ii)-catalyzed and acid-promoted highly regioselective oxidation of tautomerizable C(sp3)–H bonds adjacent to 3,4-dihydroisoquinolines using air (O2) as a clean oxidant

A novel Cu(ii)-catalyzed and acid-promoted highly regioselective oxidation of tautomerizable C(sp3)–H bonds adjacent to 1-Bn-DHIQs was developed. This method was successfully applied in the first total synthesis of canelillinoxine.

IBX-mediated oxidative addition of isocyanides to cyclic secondary amines: total syntheses of alangiobussine and alangiobussinine

The present study describes a robust and general method for the synthesis of C(1)-carboxamides through IBX-mediated oxidative addition of isocyanides to tryptolines and 1,2,3,4-tetrahydroisoquinolines. In this transformation, IBX plays a dual role of an oxidant and Lewis acid to activate imine facilitating isocyanide addition. Detailed mechanistic investigations were performed by isotopic labeling and real-time NMR experiments. The method was utilized for the gram scale syntheses of two alkaloids alangiobussine and alangiobussinine in 63% and 45% overall yield, respectively.