Construction of anti-1,2-diols bearing chiral tertiary alcohol moiety using free hydroxyacetone as aldol donor by imidazole-based prolineamide catalyst

A direct aldol reaction of free hydroxyacetone and activated ketone has been firstly achieved with a newly developed imidazole-based prolineamide catalyst. The adducts anti-1,2-diols bearing a chiral tertiary alcohol moiety were obtained in high yield (up to 92%) and stereoselectivity (up to 15:1 dr and 90% ee).     

Formation mechanism of hydroxyacetone in glucose pyrolysis: A combined experimental and theoretical study

During fast pyrolysis of biomass, hydroxyacetone (HA, also known as 1-hydroxy-2-propanone) is a vital linear ketone product from fragmentation (ring scission) of cellulose. In this study, density functional theory (DFT) calculations are employed to reveal the HA formation mechanisms and pathways from fast pyrolysis of glucose that is the cellulose-based monosaccharide. Moreover, isotopic labeling fast pyrolysis experiments were conducted to confirm the theoretical calculation results from glucose. The results indicate that during glucose pyrolysis, HA is mainly derived from C1–C2–C3 and C4–C5–C6 segments, with C1 or C6 in the methyl group of HA. The HA from C1–C2–C3 is mainly generated via the 3-ketohexose intermediate, while the formation of the HA from C4–C5–C6 mainly involves the d-fructose intermediate. In addition, the formation of HA is parallel and competitive with the formation of levoglucosan (LG, the most important pyrolytic product of glucose), and the secondary decomposition of LG will result in trace of the HA from C4–C5–C6.