<i>De Novo</i> Asymmetric Synthesis of All-<scp>d</scp>-, All-<scp>l</scp>-, and <scp>d</scp>-/<scp>l</scp>-Oligosaccharides Using Atom-less Protecting Groups
作者:Ravula Satheesh Babu、Qian Chen、Sang-Woo Kang、Maoquan Zhou、George A. O’Doherty
DOI:10.1021/ja305321e
日期:2012.7.25
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
Anticancer Agents from the Australian Tropical Rainforest: Spiroacetals EBC-23, 24, 25, 72, 73, 75 and 76
作者:Lin Dong、Heiko Schill、Rebecca L. Grange、Achim Porzelle、Jenny P. Johns、Peter G. Parsons、Victoria A. Gordon、Paul W. Reddell、Craig M. Williams
DOI:10.1002/chem.200901525
日期:2009.10.26
EBC‐23, 24, 25, 72, 73, 75 and 76 were isolated from the fruit of Cinnamomum laubatii (family Lauraceae) in the Australiantropicalrainforests. EBC‐23 (1) was synthesized stereoselectively, in nine linear steps in 8 % overall yield, to confirm the reported relative stereochemistry and determine the absolute stereochemistry. Key to the total synthesis was a series of Tietze–Smith linchpin reactions
Enantioselective Synthesis of 2-Deoxy- and 2,3-Dideoxyhexoses
作者:Michael H. Haukaas、George A. O'Doherty
DOI:10.1021/ol025844x
日期:2002.5.1
[reaction: see text] The enantioselective syntheses of C-6 O-TBS- and N-Cbz-protected 2-deoxy- and 2,3-dideoxysugars have been achieved in 6-8 steps from furfural. A combination of chemo-, regio-, and diastereoselective oxidation and reduction reactions produced deoxysugars with various C-6 substitution. A key development of this route was the use of o-nitrobenzenesulfonylhydrazide (NBSH) as a diimide
Enantioselective synthesis of 5-substituted α,β-unsaturated δ-lactones: application to the synthesis of styryllactones
作者:Joel M Harris、George A O’Doherty
DOI:10.1016/s0040-4039(99)02050-x
日期:2000.1
A flexible enantioselectivesynthesis of highly functionalized 5-substituted α,β-unsaturated δ-lactones has been achieved by applying the Sharpless catalytic asymmetric dihydroxylation to vinylfuran as the key step. The resulting diols are produced in high enantio excess and can be stereoselectively transformed into differentially protected δ-lactones through a short reaction sequence.
Palladium‐Catalyzed Stereospecific <i>S</i>‐Glycosylation by Allylic Substitution
作者:Yanyan Wang、Zhen Cao、Nengzhong Wang、Mingguo Liu、Haifeng Zhou、Long Wang、Nianyu Huang、Hui Yao
DOI:10.1002/adsc.202300129
日期:2023.5.23
S-Glycosides are considerably more stable toward chemical degradation and enzymatic hydrolysis than O-glycosides, and thioglyco-peptides/proteins also demonstrate critical bioactivities in the living system. However, the general and stereoselective synthetic strategies are still challenging. Herein, a versatile S-glycosylation approach was developed by palladium-catalyzed allylic substitution to form