C1‐Functionalization of 1,2,3,4‐Tetrahydroisoquinolines (THIQs)

Hypervalent Iodine(III)-Mediated Oxidative Cyclization of Exo-Cyclic Ene-Carbamate to Tetrahydroisoquinoline-Oxazol-2(3H)-one Derivatives

The new development of a transition-metal-free method for the synthesis of THIQ-oxazol-2(3H)-one motif from exo-cyclic ene-carbamates by using hypervalent iodine as an oxidant is reported. Various functional groups substituted on the aryl rings of the ene-carbamate substrates as well as the N- and S-heterocyclic substrates afforded the corresponding THIQ-oxazol-2(3H)-one products in up to 91 % yield. Moreover, the synthetic utility was highlighted for the synthesis of phthalide-THIQ natural product, (±)-corlumine.

Iron porphyrin-catalysed C(sp3)–H amination with alkyl azides for the synthesis of complex nitrogen-containing compounds

With the readily prepared iron porphyrin complex as a catalyst and starting with alkyl azides, a panel of nitrogen-containing skeletons representing the families of natural alkaloids and bioactive compounds could be prepared in good yields.

Oxidative α-Functionalization of 1,2,3,4-Tetrahydroisoquinolines Catalyzed by a Magnetically Recoverable Copper Nanocatalyst. Application in the Aza-Henry Reaction and the Synthesis of 3,4-Dihydroisoquinolones

The oxidative α-functionalization of 2-aryl-1,2,3,4-tetrahydroisoquinolines (THIQs) promoted by a versatile heterogeneous nanocatalyst consisting of copper nanoparticles immobilized on silica-coated maghemite (CuNPs/MagSilica) has been accomplished. The methodology was successfully applied in the cross-dehydrogenative coupling (CDC) reaction of N-aryl THIQs and other tertiary amines with nitromethane as a pro-nucleophile (aza-Henry reaction) and the α-oxidation of THIQs with O₂ as a green oxidant. Phosphite, alkyne, or indole derivatives were also shown to be suitable candidates for their use as pro-nucleophiles in the CDC reaction with THIQs. The catalyst, with very low copper loading (0.4-1.0 mol % Cu), could be easily recovered by means of an external magnet and reused in four cycles without significant loss of activity.