Copper-Catalyzed Alkenylation of Alcohols with β-Nitrostyrenes via a Radical Addition–Elimination Process

Abstract

A new method for the preparation of allylic alcohol derivatives has been developed via a radical mechanism using DTBP as the radical initiator promoted by copper salt. The C(sp 3 )-H bond in various alcohols, toluene derivatives, and alkanes were successfully converted into C-C bonds to yield the desired products in moderate to good yields.

Iridium-, Ruthenium-, and Nickel-Catalyzed C–C Couplings of Methanol, Formaldehyde, and Ethanol with π-Unsaturated Pronucleophiles via Hydrogen Transfer

“…Ethanol is the Proteus of alcohols, yet beyond ethanol-to-butanol and related Guerbet-type processes, catalytic C–C couplings of ethanol are rare and (notwithstanding our own work) , are limited to isolated cases in which racemic products are formed . As catalytic enantioselective C–C couplings of ethanol are absent from the chemical literature, we investigated its C–C coupling with allylic acetates using our signature π-allyliridium– C,O -benzoate catalysts (Scheme ).…”

Alcohols as Substrates in Transition-Metal-Catalyzed Arylation, Alkylation, and Related Reactions

“…For example, Ishii and colleagues disclosed a method for the α-vinylation of superstoichiometric quantities of secondary alcohols with alkynes 776 using N-hydroxyphthalimide (NHPI) alongside a cobalt catalyst to facilitate radical formation (Scheme 84a). The authors proposed that NHPI is converted into its corresponding Ocentered radical that can abstract a hydrogen from the secondary alcohol, enabling subsequent addition to the 777 Yuan describing reactions with nitrostyrenes in 2015, 778 and Fang disclosing alkenylation with cinnamic acids in 2017. 779 Li and colleagues utilized palladium catalysis in the αarylation of primary aliphatic alcohols with electron-deficient N-heterocycles in 2011 (Scheme 85a).…”

“…The authors proposed that NHPI is converted into its corresponding Ocentered radical that can abstract a hydrogen from the secondary alcohol, enabling subsequent addition to the electron-deficient unsaturated species. Further methods for the decarboxylative α-vinylation of alcohols have been established, with Liu disclosing a copper-catalyzed alkenylation with cinnamic acids in 2012 (Scheme 84b), 777 Yuan describing reactions with nitrostyrenes in 2015, 778 and Fang disclosing alkenylation with cinnamic acids in 2017. 779 Li and colleagues utilized palladium catalysis in the αarylation of primary aliphatic alcohols with electron-deficient N-heterocycles in 2011 (Scheme 85a).…”

Denitrative Cross-Couplings of Nitrostyrenes

“…Although each proposal differs in detail, the main three characteristic steps feature in all proposals. Firstly, carbon- or heteroatom-centered radical 4 is generated in situ by various methods from precursors 6 – 33 [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ]. These include a thermal homolytic cleavage of labile bonds, metal-catalyzed and photochemically initiated processes.…”

“…An alkenylation of alcohols with β-nitrostyrenes 1 via a radical addition–elimination process was discovered by Yuan in 2015 ( Scheme 13 ) [ 30 ]. The copper acetate catalyzed process performed at a very high temperature enabled the formation of miscellaneous allylic alcohols 3 , from a broad range of readily available primary and secondary alcohols 17 .…”