Sustainable and recyclable heterogenous palladium catalysts from rice husk-derived biosilicates for Suzuki-Miyaura cross-couplings, aerobic oxidations and stereoselective cascade carbocyclizations

Samson Afewerki; Ana Franco; Alina M Balu; Cheuk-Wai Tai; Rafael Luque; Armando Córdova

doi:10.1038/s41598-020-63083-8

Sustainable and recyclable heterogenous palladium catalysts from rice husk-derived biosilicates for Suzuki-Miyaura cross-couplings, aerobic oxidations and stereoselective cascade carbocyclizations

Sci Rep. 2020 Apr 14;10(1):6407. doi: 10.1038/s41598-020-63083-8.

Authors

Samson Afewerki^{1

2}, Ana Franco³, Alina M Balu³, Cheuk-Wai Tai^{4

5}, Rafael Luque^{6

7}, Armando Córdova^{8

9}

Affiliations

¹ Department of Natural Sciences, Mid Sweden University, Sundsvall, SE-85170, Sweden. samson.afewerki20@gmail.com.
² Berzelii Center EXSELENT on Porous Materials, Stockholm University, Stockholm, SE-10691, Sweden. samson.afewerki20@gmail.com.
³ Departamento de Química Orgánica, Universidad de Córdoba, Campus de Rabanales Edificion Marie Curie (C-3), Ctra Nnal IV-A, Km 396, 14014, Cordoba, Spain.
⁴ Berzelii Center EXSELENT on Porous Materials, Stockholm University, Stockholm, SE-10691, Sweden.
⁵ Department of Environmental and Materials Chemistry, Stockholm University, Stockholm, SE-10691, Sweden.
⁶ Departamento de Química Orgánica, Universidad de Córdoba, Campus de Rabanales Edificion Marie Curie (C-3), Ctra Nnal IV-A, Km 396, 14014, Cordoba, Spain. rafael.luque@uco.es.
⁷ Peoples friendship University of Russia (RUDN University), 6 Miklukho Maklaya str, 117198, Moscow, Russia. rafael.luque@uco.es.
⁸ Department of Natural Sciences, Mid Sweden University, Sundsvall, SE-85170, Sweden. armando.cordova@miun.se.
⁹ Berzelii Center EXSELENT on Porous Materials, Stockholm University, Stockholm, SE-10691, Sweden. armando.cordova@miun.se.

Abstract

A new eco-friendly approach for the preparation of sustainable heterogeneous palladium catalysts from rice husk-derived biogenic silica (RH_P-Si and RH_U-Si). The designed heterogeneously supported palladium species (RH_P-Si-NH₂-Pd and RH_U-Si-NH₂-Pd) were fully characterized and successfully employed as catalysts for various chemical transformations (C-C bond-forming reactions, aerobic oxidations and carbocyclizations). Suzuki-Miyaura transformations were highly efficient in a green solvent system (H₂O:EtOH (1:1) with excellent recyclability, providing the cross-coupling products with a wide range of functionalities in high isolated yields (up to 99%). Palladium species (Pd(0)-nanoparticles or Pd(II)) were also efficient catalysts in the green aerobic oxidation of an allylic alcohol and a co-catalytic stereoselective cascade carbocyclization transformation. In the latter case, a quaternary stereocenter was formed with excellent stereoselectivity (up to 27:1 dr).

Publication types

Research Support, Non-U.S. Gov't