33647-85-7Relevant articles and documents
Manipulating the enone moiety of levoglucosenone: 1,3-Transposition reactions including ones leading to isolevoglucosenone
Ma, Xinghua,Liu, Xin,Yates, Patrick,Raverty, Warwick,Banwell, Martin G.,Ma, Chenxi,Willis, Anthony C.,Carr, Paul D.
, p. 5000 - 5011 (2018/06/20)
The manipulation of the enone moiety associated with the biomass-derived, homochiral and now abundant compound levoglucosenone (1) is described. While the trichloroacetimidates derived from the allylic alcohols 3 and 4 failed to engage in Overman-type rea
The conversion of levoglucosenone into isolevoglucosenone
Ma, Xinghua,Anderson, Natasha,White, Lorenzo V.,Bae, Song,Raverty, Warwick,Willis, Anthony C.,Banwell, Martin G.
, p. 593 - 599 (2015/04/27)
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 γ-lactones 5 and 6 rather than the required epoxy-ketones 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.
Total synthesis of (+)-ambruticin S
Berberich, Stephen M.,Cherney, Robert J.,Colucci, John,Courillon, Christine,Geraci, Leo S.,Kirkland, Thomas A.,Marx, Matthew A.,Schneider, Matthias F.,Martin, Stephen F.
, p. 6819 - 6832 (2007/10/03)
A convergent total synthesis of the novel antifungal agent ambruticin S (1) has been completed from the assembly of intermediates 18, 33 and 52 that served as the respective A-, B-, and C-ring precursors. The first generation approach to a potential A-ring intermediate eventuated in the synthesis of 9a via a route that featured oxidation of the dihydroxy furan 2 and elaboration of the dihydropyranone 3 derived therefrom. Although 9a served as a precursor of 31E to complete a formal synthesis of 1, there were several inefficiencies associated with the preparation of 9a. A more expedient and efficient route to an A-ring subunit was devised that commenced with the carbohydrate-derived bisacetonide aldehyde 10 and produced 18 in five steps and 46% overall yield. The synthesis of the cyclopropyl sulfone 33 was initiated with the enantioselective cyclopropanation of 19 catalyzed by Rh 2[5(S)-MEPY]4. Ring opening of the resultant lactone 20 followed by a series of refunctionalizations gave 33 in a total of seven steps and 46% yield from 19. Coupling of the A- and B-ring precursors 18 and 33 was then achieved via a modified Julia coupling followed by deprotection and oxidation to furnish the key intermediate 35. The dihydropyran core of the C-ring subunit precursor 49 was formed from the ring closing metathesis of the diene 48, which was prepared in three steps from the known epoxide 45, followed by oxidation. A chelation-controlled addition to the methyl ketone 49 set the stage for a stereoselective [2,3]-Wittig rearrangement that delivered the alcohol 51 that was then transformed in two steps to the sulfone 52. A traditional Julia coupling of 52 and 35 proceeded with excellent stereoselectivity, and subsequent removal of the various protecting groups gave ambruticin S (1). The longest linear sequence was 13 steps and proceeded in 4. 3% overall yield.
