Organocatalytic Synthesis of Higher-Carbon Sugars: Efficient Protocol for the Synthesis of Natural Sedoheptulose and d-Glycero-l-galacto-oct-2-ulose.
Herein we report a short and efficient protocol for the synthesis of naturally occurring higher-carbon sugars-sedoheptulose (d-altro-hept-2-ulose) and d-glycero-l-galacto-oct-2-ulose-from readily available sugar aldehydes and dihydroxyacetone (DHA). The key step includes a diastereoselective organocatalytic syn-selective aldol reaction of DHA with d-erythrose and d-xylose, respectively. The methodology presented can be expanded to the synthesis of various higher sugars by means of syn-selective carbon-carbon-bond-forming aldol reactions promoted by primary-based organocatalysts. For example, this methodology provided useful access to d-glycero-d-galacto-oct-2-ulose and 1-deoxy-d-glycero-d-galacto-oct-2-ulose from d-arabinose in high yield (85 and 74 %, respectively) and high stereoselectivity (99:1).
Institute of Organic Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland.
Oskar
O
Popik
Faculty of Chemistry Jagiellonian University Ingardena 3 30-060 Krakow Poland.
Monika
M
Pasternak-Suder
Faculty of Chemistry Jagiellonian University Ingardena 3 30-060 Krakow Poland.
Sebastian
S
Baś
Institute of Organic Chemistry Polish Academy of Sciences Kasprzaka 44/5201-224 Warsaw Poland; Faculty of Chemistry Jagiellonian University Ingardena 330-060 Krakow Poland.
Jacek
J
Mlynarski
aldol reaction; asymmetric synthesis; carbohydrates; natural products; organocatalysis