Formation of β-cyano-ketones through cyanide-promoted ring-opening of cyclic organic carbonates

Abstract

Here we disclose a method for the unexpected decarboxylative cyanide-assisted ring-opening reaction of a series of vinyl cyclic carbonates. At elevated temperature, the attack of a cyanide nucleophile at the...

Construction of Polycarbonates with Pendant Multifunctional Groups via a One-Step CO2/ Diepoxide Copolymerization Approach

“…Making use of a preference of (ONSO)­CrCl (ethylene-bridged imine-thiobis­(phenolate) chromium complex)-mediated coupling reaction of a cycloaliphatic epoxide with CO 2 to generate poly­(cyclohexene carbonate) (PCHC), while product selectivity toward cyclic carbonate (CC) at the coupling reaction of the terminal epoxide and CO 2 , we have developed a straightforward method to prepare the APCs containing two different functional groups (ethylene oxide (EO) and ethylene carbonate (EC)) via the (ONSO)­CrCl-mediated copolymerization of CO 2 with VCD in one step (Scheme c) . Such a dual-functionalized polycarbonate can serve as a powerful building block because of the versatile reaction of the CC − and epoxide ,,− groups. One drawback in this work is the catalyst using heavy Cr as an active species.…”

Unusual DBU-catalyzed decarboxylative formation of allylic thioethers from vinyl cyclic carbonates and thiols

“…These conversions are best described as decarboxylative allylation reactions and a wide scope of nucleophiles can be used as reaction partners. 12 Following our interest in the ring-opening of cyclic carbonates and the unique endo-cyclic attack of cyanide prior to ring-opening of VCCs, 11 we envisioned that the use of other nucleophiles (i.e., thiols) would offer similar types of reactivity as regioselective, decarboxylative thiolation of the methylene carbon of cyclic carbonates has been reported in the creation of new functional polymers. 13 However, in the course of our studies, we encountered a distinct reactivity behavior of VCCs in the presence of thiols, with the nucleophilic attack occurring at the exo-cyclic double bond (Scheme 1c), affording formally (after loss of CO 2 ) allylic thioethers as products.…”

“…8 Although the nucleophilic ring-opening of cyclic carbonates is usually preferred at the electrophilic carbon of the carbonate group, there are few examples of the “methylene” attack reported in the literature (Scheme 1b). These processes occur at elevated temperatures with extrusion of CO 2 , and examples of amine, 9 thiol 10 and cyanide based nucleophiles 11 have been reported.…”

“…These conversions are best described as decarboxylative allylation reactions and a wide scope of nucleophiles can be used as reaction partners. 12 Following our interest in the ring-opening of cyclic carbonates and the unique endo -cyclic attack of cyanide prior to ring-opening of VCCs, 11 we envisioned that the use of other nucleophiles ( i.e. , thiols) would offer similar types of reactivity as regioselective, decarboxylative thiolation of the methylene carbon of cyclic carbonates has been reported in the creation of new functional polymers.…”