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

Abstract

An efficient method for synthesizing C(1)-carboxamides through IBX-mediated oxidative addition of isocyanides to cyclic secondary amines has been reported.

Using Methanol as a Formaldehyde Surrogate for Sustainable Synthesis of N‐Heterocycles via Manganese‐Catalyzed Dehydrogenative Cyclization

“…[ 24 ] Lastly, 3m was selectively transformed into carboxamide 8d through IBX‐mediated oxidative addition with tert ‐butyl isocyanide. [ 25 ]…”

Recent Advances in the Synthesis of β-Carboline Alkaloids

“…The sensitive OH moiety of the indole was protected by a TBDMS group, which was removed under mild conditions in the final step with CsF (Scheme 10). The IBX-mediated total synthesis of alangiobussine (22) and alangiobussinine (23) was achieved through the oxidative addition of isocyanide 146 to tryptoline (145) [125]. The general method (Scheme 11) represents an efficient preparation for imino-carboxamides, where tetrahydroisoquinolines and tryptolines were reacted with isocyanides.…”

The Mechanistic Perspective of IV Iodoxolones

“…Until 2019, triptomine or 1,2,3,4‐tetrahydroisoquinoline C(1) acylation was only possible for N(2) pre‐functionalised substrates however, by applying IBX 3 in DMSO, Ambule et al. formed C(1)‐imino‐carboxamide in good yeild [112] . The authors proposed two alternative mechanisms, which are depicted in Scheme 67: Both initiate from dehydrogenation of the triptoline 395 C(1)‐N(2) σ‐bond by 3 , as supported by a 75% yeild of 3,4‐dihydro‐ β‐ carboline 396 if 3 (1 equiv.)…”

“…Until 2019, triptomine or 1,2,3,4-tetrahydroisoquinoline C(1) acylation was only possible for N(2) pre-functionalised substrates however, by applying IBX 3 in DMSO, Ambule et al formed C(1)-imino-carboxamide in good yeild. [112] The authors proposed two alternative mechanisms, which are depicted in between oxygen and nitrogen atoms, as 1,3-hydrogen shift such as step 399à400 is suggested to require a catalyst. [113] The alternative pathway in Scheme 67 involves iodine(V) hydroxyl ligand transfer to the nitrile carbon of 12-I-5 intermediate 398, to form 10-I-4 species 401.…”