Selective Reductive Dimerization of CO2 into Glycolaldehyde

The selective dimerization of CO2 into glycolaldehyde is achieved in a one-pot two-step process via formaldehyde as a key intermediate. The first step concerns the iron-catalyzed selective reduction of CO2 into formaldehyde via formation and controlled hydrolysis of a bis(boryl)acetal compound. The second step concerns the carbene-catalyzed C-C bond formation to afford glycolaldehyde. Both carbon atoms of glycolaldehyde arise from CO2 as proven by the labeling experiment with (CO2)-C-13. This hybrid organometallic/organic catalytic system employs mild conditions (1 atm of CO2, 25 to 80 degrees C in less than 3 h) and low catalytic loadings (1 and 2.5%, respectively). Glycolaldehyde is obtained in 53% overall yield. The appealing reactivity of glycolaldehyde is exemplified (i) in a dimerization process leading to C-4 aldose compounds and (ii) in a tri-component Petasis-Borono-Mannich reaction generating C-N and C-C bonds in one process.

Automated summary

The selective dimerization of CO2 into glycolaldehyde is achieved in a one-pot two-step process via formaldehyde as a key intermediate. The hybrid organometallic/organic catalytic system shows good reactivity under mild conditions and low catalytic loadings, resulting in a promising overall yield of glycolaldehyde. The study demonstrates the potential of glycolaldehyde in various reactions, including dimerization and a tri-component reaction generating C-N and C-C bonds.