Dihydroxybenzene‐derived ILs as Halide‐Free, Single‐component Organocatalysts for CO2 Insertion Reactions

Abstract A series of dihydroxybenzene‐derived ILs was synthesised via a halide‐free, eco‐friendly methodology and fully characterized. Their activity as single component catalyst towards synthesis of cyclic organic carbonates (COCs) via CO 2 insertion into terminal epoxides was evaluated, observing that methyltrioctylammonium hydroquinolate, [N 1888 ][HYD], was the most active catalyst in the proposed optimized conditions ([N 1888 ][HYD] 10 % mol, T=120 °C, t=6 h, p 0 (CO 2 )=2.0 MPa, 12 examples, conversion >99 %, yield up to 98 %). Interestingly, [N 1888 ][HYD] was also an active catalyst for CO 2 insertion reactions with cyclohexene oxide (CHO), observing formation of both the COC and polycarbonate product. It is proposed that for p 0 (CO 2 )≥1.0 MPa, the catalytically active species is the hemicarbonate derivative of the hydroquinolate anion, active towards epoxide ring opening via an unusual hemicarbonate‐alkoxide pathway.