title: Transition-metal-catalyzed C-H bond functionalizations: feasible access to a diversity-oriented β-carboline library.
abstract: Diversification of the β-carboline skeleton has been demonstrated to assemble a β-carboline library starting from the tetrahydro-β-carboline framework. This strategy affords feasible access to heteroaryl-, aryl-, alkenyl-, or alkynyl-substituted β-carbolines at the C1, C3, or C8 position through three categorically different types of transition-metal-catalyzed CC bond-forming reactions, in the presence of multiple potentially reactive positions. These site-selective functionalizations include; 1) the Cu-catalyzed C1/C3-selective decarboxylative C sp 3C sp 2 and C sp 3Csp coupling of hexahydro-β-carboline-3-carboxylic acid with a CH bond of a heteroarene or terminal alkyne; 2) the chelation-assisted Pd-catalyzed C1/C8-selective CH arylation of hexahydro-β-carboline with aryl boron reagents; and 3) the chelation-assisted Pd-catalyzed C1/C3-selective oxidative CH/CH cross-coupling of β-carboline-N-oxide with arenes, heteroarenes, or alkenes. The saturated structural feature of the hexahydro-β-carboline framework can increase reactivity and control site selectivity. The robustness of these approaches has been demonstrated through the synthesis of hyrtioerectine analogues and perlolyrine. We believe that these strategies could provide inspiration for late-stage diversifications of bioactive core scaffolds.
authors: Key Laboratory of Green Chemistry and Technology of Ministry of Education, College of Chemistry, and State Key Laboratory of Biotherapy, West China Medical School, Sichuan University, 29 Wangjiang Road, Chengdu 610064 (P. R. China), Fax: (+86) 28-85412203.
authors: Ningjie
authors: N
authors: Wu
authors: Feijie
authors: F
authors: Song
authors: Lipeng
authors: L
authors: Yan
authors: Juan
authors: J
authors: Li
authors: Jingsong
authors: J
authors: You
mesh_terms: D002243:Carbolines / Q000138:chemical synthesis / Q000737:chemistry*; D002384:Catalysis; D002614:Chelating Agents / Q000737:chemistry; D005663:Furans / Q000138:chemical synthesis / Q000737:chemistry; D006860:Hydrogen Bonding; D026121:Indole Alkaloids / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D010984:Platinum / Q000737:chemistry; D028561:Transition Elements / Q000737:chemistry*
chemical_list: D002243:Carbolines; D002614:Chelating Agents; D005663:Furans; D026121:Indole Alkaloids; D028561:Transition Elements; C505315:hyrtioerectine A; C055781:perlolyrine; D010984:Platinum; C049236:carboline-3-carboxylic acid
keywords: CH bond functionalization; arylation; decarboxylative coupling; oxidative cross-coupling; β-carboline