Hydrogenation of Epoxides to Anti‐Markovnikov Alcohols over a Nickel Heterogenous Catalyst Prepared from Biomass (Rice) Waste

Abstract

The synthesis of primary alcohols (from olefins) is an important and challenging transformation, as most of the current methods suffer from regioselectivity issues. This work describes the utilization of rice husk (RH) from agricultural waste as support for the preparation of a catalyst for the conversion of olefin oxides to primary alcohols. The catalyst was synthesized by pyrolysis of RH impregnated with nickel, and characterized by IR, AAS, XRD, BET, XPS, TEM, and TPD technics. The catalyst shows excellent activity and selectivity towards anti-Markovnikov alcohols, acting simultaneously as Brønsted acid, solid Lewis acid, and as hydrogenation catalyst. A substrate screening was done, the catalyst's recycling stability was assessed, and a plausibly reaction mechanism was proposed.

BF3-promoted selective catalytic hydroboration of epoxides to primary alcohols

“…[18][19][20][21][22] Hydroboration occurs readily when substrates react with the boron reagents, leading to the formation of anti-Markovnikov products. 21,23,24 As a mild reductant and boron source, pinacolborane (HBpin) is promising in the hydroboration of carbonyl compounds, unsaturated hydrocarbons, as well as epoxides. 25,26 For instance, bis(imino)pyridine cobalt could catalyze hydroboration of terminal alkynes with HBpin, 27 and metal salt LiBr had been proved to be effective as a catalyst for hydroboration of aldehydes and ketones in the presence of HBpin.…”