The Conversion of Levoglucosenone into Isolevoglucosenone

Abstract

Levoglucosenone (1), a compound that will soon be available in tonne quantities through the pyrolysis of acid-treated lignocellulosic biomass, has been converted into isolevoglucosenone (2) using Wharton rearrangement chemistry. Treatment of compound 1 with alkaline hydrogen peroxide gave the g-lactones 5 and 6 rather than the required epoxyketones 3 and/or 4. However, the latter pair of compounds could be obtained by an initial Luche reduction of compound 1, electrophilic epoxidation of the resulting allylic alcohol 8 and oxidation of the product oxiranes 9 and 10. Independent treatment of compounds 3 and 4 with hydrazine then acetic acid followed by oxidation of the ensuing allylic alcohols finally afforded isolevoglucosenone (2). Details of the single-crystal X-ray analyses of epoxy-alcohols 9 and 10 are reported.

The Exploitation of Enzymatically‐Derived cis‐1,2‐Dihydrocatechols and Related Compounds in the Synthesis of Biologically Active Natural Products

“…With the assistance of colleagues in the biotech industry we have also produced new cis ‐1,2‐dihydrocatechols such as 199 as well as beginning to explore the chemistry of levoglucosenone ( 200 ), a material that is now available in tonne quantities through pyrolysis of acid‐impregnated waste paper and other cellulosic materials. As part of that study we have been able to devise ways in which compound 200 is converted into its so‐called quasi‐enantiomer isolevoglucosenone ( 201 ) . We have also established a method for the four‐step conversion of cis ‐1,2‐dihydrocatechol 1 (X=Br) into the 5,6‐ trans ‐dihydroxylated α‐bromocyclohexenone 202 , another potentially very useful chiron.…”

A Domino Epoxide Ring‐Opening Xanthate Migration Reaction: An Alternative Entry to Thiosugars

“…The steric restriction imposed by the 1,6‐anhydro bridge in 3 resulted in the preferential formation of epoxide 4 although this structural factor does not completely overcome the directing ability of the hydroxyl group, obtaining significant quantities of 5 as well. Despite the α‐epoxide could be obtained in a highly stereoselective manner by blocking the directing effect of the hydroxyl group by acetylation, we envisaged the formation of the two isomers to explore the influence of the relative stereochemistry of the starting material in the reaction outcome.…”

“…71–73 °C (CH 2 Cl 2 /hexane). [ α ] D 20 = +56 C, ( c 0.5, CH 3 OH); δ H (300 MHz CDCl 3 ) 5.29 (d, 1 H, 3 J 1,2 = 3.4 Hz, H‐1), 4.81 (t, 1 H, 3 J 5,4 = 3 J 5,6 = 4.9 Hz, H‐5), 3.99 (d, 1 H, 2 J gem = 6.9, H‐6), 3.78 (m, 2 H, H‐2, H‐4), 3.55 (m, 1 H, H‐6), 3.33 (m, 1 H, H‐3); δ C (75 MHz CDCl 3 ) 97.8 (C‐1), 71.7 (C‐5), 66.5 (C‐2), 63.9 (C‐6), 57.3 (C‐4), 50.2 (C‐3) …”

Manipulating the enone moiety of levoglucosenone: 1,3-Transposition reactions including ones leading to isolevoglucosenone

“…3 The most obvious site for manipulation is the enone moiety and a range of methods for doing so has been reported in the literature, 1,4 including by us. 5 In particular, and like others, 3 we have sought to convert compound 1 into its quasienantiomer isolevoglucosenone (2). In our work 5 this was achieved using Wharton rearrangement chemistry and these studies prompted us to consider other means by which the required and related 1,3-transposition processes could be implemented within the 6,8-dioxabicyclo [3.2.1]octane framework associated with levoglucosenone.…”