Stereocontrolled Photocyclization of 1,2-Diketones: Application of a 1,3-Acetyl Group Transfer Methodology to Carbohydrates

Abstract

Photolysis of 1-glycosyl-2,3-butanodione derivatives using visible light is a mild and selective procedure for the synthesis of chiral 1-hydroxy-1-methyl-5-oxaspiro[3.5]nonan-2-one carbohydrate derivatives. The results strongly suggest that stereocontrol of the cyclization is dependent on conformational and stereoelectronic factors. Further oxidative opening of the 1-hydroxy-1-methyl-2-cyclobutanone moiety affords new C-ketoside derivatives either in C- and O-glycoside series. This tandem two-step process could be considered to be a stereocontrolled 1,3-transference of an acetyl group, and it can be applied either to pyranose and furanose models.

Studies in organic and physical photochemistry – an interdisciplinary approach

“…For example, the glucose derivative 22 was efficiently transformed into the corresponding hydroxycyclobutanone derivative 23 (Scheme 4). 26 Only one anomer was obtained which was generated under retention of configuration. Furthermore, only one configuration was generated at the quaternary center carrying the hydroxyl function.…”

Visible‐Light‐Induced CC Bond Cleavage of Enaminones for the Synthesis of 1,2‐Diketones and Quinoxalines in Sustainable Medium

“…Therefore, as the main building blocks, 1,2-diketones have been broadly used in the synthesis of many important organic products such as a-hydroxyl ketone, [1] N-containing heterocycles, [2] and carbohydrates. [3] More notably,t he 1,2-diketone fragment has been found to be present in an umber of biologically relevant organic molecules. [4] During the past decades, the efforts of chemists have led to the establishmento fs everald ifferent types of strategies towardt he synthesis of 1,2-diketones.…”

Sequential Norrish Type II Photoelimination and Intramolecular Aldol Cyclization of 1,2‐Diketones in Carbohydrate Systems: Stereoselective Synthesis of Cyclopentitols

“…Within this context, and in connection with our ongoing research programs on the reactivity of 1,2‐diketones6 and hydrogen‐atom transfer (HAT) promoted by alkoxyl radicals in carbohydrate chemistry,7 the aim of the present study has been to explore the photochemical reactivity of nono‐2,3‐diuloses (e.g. 1 , Scheme ) 8.…”