Selective Stereoretention of Carbohydrates upon C-C Cleavage Enabling D-Glyceric Acid Production with High Optical Purity over a Ag/γ-Al2O3 Catalyst.
Angew Chem Int Ed Engl
; 63(22): e202403547, 2024 May 27.
Article
em En
| MEDLINE
| ID: mdl-38485666
ABSTRACT
Chiral carboxylic acid production from renewable biomass by chemocatalysis is vitally important for reducing our carbon footprint, but remains underdeveloped. We herein establish a strategy that make use of a stereogenic center of biomass to achieve a rare example of D-glyceric acid production with the highest yield (86.8 %) reported to date as well as an excellent ee value (>99 %). Unlike traditional asymmetric catalysis, chiral catalysts/additives are not required. Ample experiments combined with quantum chemical calculations established the origins of the stereogenic center and catalyst performance. The chirality at C4 in D-xylose was proved to be retained and successfully delivered to C2 in D-glyceric acid during C-C cleavage. The remarkable cooperative-roles of Ag+ and Ag0 in the constructed Ag/γ-Al2O3 catalyst are disclosed as the crucial contributors. Ag+ was responsible for low-temperature activation of D-xylose, while Ag0 facilitated the generation of active O* from O2. Ag+ and active O* cooperatively promoted the precise cleavage of the C2-C3 bond, and more importantly O* allowed the immediate fast oxidization of the D-glyceraldehyde intermediate to stabilize D-glyceric acid, thereby inhibiting the side reaction that induced racemization. This strategy makes a significant breakthrough in overcoming the limitation of poor enantioselectivity in current chemocatalytic conversion of biomass.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Angew Chem Int Ed Engl
Ano de publicação:
2024
Tipo de documento:
Article