81389-89-1Relevant academic research and scientific papers
Iridium-Catalyzed Dynamic Kinetic Stereoselective Allylic Etherification of Achmatowicz Rearrangement Products
Zhu, Zhongpeng,Wang, Hao-Yuan,Simmons, Christopher,Tseng, Po-Sen,Qiu, Xiang,Zhang, Yu,Duan, Xiyan,Yang, Jing-Kui,Tang, Weiping
, p. 595 - 599 (2018)
We recently developed a novel Ir-catalyzed dynamic kinetic isomerization reaction for Achmatowicz rearrangement products. In this update, we show that products derived from the Achmatowicz rearrangement can also undergo Ir-catalyzed dynamic kinetic allylic etherification in the presence of an appropriate ligand and additive to afford useful intermediates for the synthesis of carbohydrates. The addition of the triphenyl phosphite ligand shuts down the isomerization pathway and promotes the allylic etherification pathway. The addition of diphenyl phosphate improved the diastereoselectivity for the addition reaction. Interestingly, opposite diastereoselectivity was observed for sterically demanding alcohol nucleophiles compared to less sterically demanding alcohol nucleophiles. The method was also applied to the synthesis of several 2,3-dideoxypyranosides. (Figure presented.).
Chiral Catalyst-Directed Dynamic Kinetic Diastereoselective Acylation of Lactols for de Novo Synthesis of Carbohydrate
Wang, Hao-Yuan,Yang, Ka,Yin, Dan,Liu, Can,Glazier, Daniel A.,Tang, Weiping
, p. 5272 - 5275 (2015/11/18)
The control of the stereochemistry at the anomeric position is still one of the major challenges of synthetic carbohydrate chemistry. We have developed a new strategy consisting of a chiral catalyst-directed acylation followed by a palladium-catalyzed gly
De novo asymmetric synthesis of All-d-, All-l-, and d-/l-oligosaccharides using atom-less protecting groups
Babu, Ravula Satheesh,Chen, Qian,Kang, Sang-Woo,Zhou, Maoquan,O'Doherty, George A.
, p. 11952 - 11955 (2012/09/07)
Oligosaccharide synthesis is hindered by the need for multiple steps as well as numerous selective protections and deprotections. Herein we report a highly efficient de novo route to various oligosaccharide motifs, of use for biological and medicinal structure activity studies. The key to the overall efficiency is the judicious use of asymmetric catalysis and synthetic design. These green principles include the bidirectional use of highly stereoselective catalysis (Pd(0)-catalyzed glycosylation/post-glycosylation). In addition, the chemoselective use of C-C and C-O π-bond functionality, as atom-less protecting groups as well as an anomeric directing group (via a Pd-π-allyl), highlights the atom-economical aspects of the route to a divergent set of natural and unnatural oligosaccharides (i.e., various d-/l-diastereomers of oligosaccharides as well as deoxysugars which lack C-2 anomeric directing groups). For example, in only 12 steps, the construction of a highly branched heptasaccharide with 35 stereocenters was accomplished from an achiral acylfuran.
Synthesis of Benzannelated Pyranosides
Card, Peter J.
, p. 2169 - 2173 (2007/10/02)
Ethyl and benzyl 2,3-dideoxy-α-D-glycero-hex-2-enopyranosid-4-uloses (e.g., 9-11) were prepared from D-glucal.The enones reacted with 1-methoxy-1,3-butadiene or 1--1,3-butadiene to afford the corresponding cycloadducts.DDQ aromatization and subsequent elaboration of the cycloadducts gave benzannelated pyranosides.Amino sugar derivatives also were prepared.Aromatization of the (trimethylsilyl)oxy adducts directly afforded the corresponding phenols, but the reaction was found to be of limited scope.The stereochemistry of intermediates and products and subtleties of the DDQ reaction are discussed.
