Bifunctional thiosquaramide catalyzed asymmetric reduction of dihydro-β-carbolines and enantioselective synthesis of (-)-coerulescine and (-)-horsfiline by oxidative rearrangement
Autor
Sathish, Manda
Nachtigall, Fabiane Manke
Santos, Leonardo S.
Resumen
Tetrahydro-β-carboline (THBC) is a tricyclic ring system that can be found in a large number of bioactive alkaloids. Herein, we report a simple and efficient method for the synthesis of enantiopure THBCs through a chiral thiosquaramide (11b) catalyzed imine reduction of dihydro-β-carbolines (17a-f). The in situ generated Pd-H employed as hydride source in the reaction of differently substituted chiral THBCs (18a-f) afforded high selectivities (R isomers, up to 96% ee) and good isolated yields (up to 88%). Moreover, the chiral thiosquaramide used also afforded exceptional catalyst activity in the syntheses of (-)-coerulescine (5) and (-)-horsfiline (6) with excellent enantioselectivities up to 98% and 93% ee, respectively, via an enantioselective oxidative rearrangement approach.
Colecciones
Ítems relacionados
Mostrando ítems relacionados por Título, autor o materia.
-
Article
TCCA-mediated oxidative rearrangement of tetrahydro-β-carbolines: Facile access to spirooxindoles and the total synthesis of (±)-coerulescine and (±)-horsfiline (2021)
Sathish, Manda; Sakla, Akash P.; Nachtigall, Fabiane Manke; Santos, Leonardo S.; Shankaraiah, N. (Royal Society of Chemistry, 2021-04-15)Multi-reactive centered reagents are beneficial in chemical synthesis due to their advantage of minimal material utilization and formation of less by-products. Trichloroisocyanuric acid (TCCA), a reagent with three reactive ... -
Article
Mechanistic study of the competitiveness between branched and linear polyethylene production on: N-arylcyano-β-diketiminate nickel hydride (2020)
Ortega, Daniela E.; Cortés-Arriagada, Diego; Trofymchuk, Oleksandra S.; Manke Nachtigall, Fabiane; Santos, Leonardo S.; Rojas, René S.; Toro-Labbé, Alejandro (Royal Society of Chemistry, 2020-09-21)This paper provides a guide to identify and understand the mechanistic origin of the catalytic activity and selectivity in the production of linear and branched polyethylene through a nickel hydride catalyst. Nickel active ... -
Article
How does reducing sodium impact the proteolysis and texture in salted meat along 180 days of shelf life? (2021)
Vidal, V. A.S.; Manke Nachtigall, Fabiane; Mara Baseggio, Andressa; Maróstica Júnior, Mário Roberto; Santos, Leonardo S.; Rodrigues Pollonio, Marise Aparecida (United Arab Emirates University, 2020)Sodium reduction in salted meat is a major technological challenge due to the technological functions of NaCl, responsible for the reduction of water activity and consequent microbiological safety, stability during shelf ...