4,6-O-[1-cyano-2-(2-iodophenyl)ethylidene] acetals. improved second-generation acetals for the stereoselective formation of beta-D-mannopyranosides and regioselective reductive radical fragmentation to beta-D-rhamnopyranosides. scope and limitations.

The Journal of Organic Chemistry
David Crich, Albert A Bowers

Abstract

The [1-cyano-2-(2-iodophenyl)]ethylidene group is introduced as an acetal-protecting group for carbohydrate thioglycoside donors. The group is easily introduced under mild conditions, over short reaction times, and in the presence of a wide variety of other protecting groups by the reaction of the 4,6-diol with triethyl (2-iodophenyl)orthoacetate and camphorsulfonic acid, followed by trimethylsilyl cyanide and boron trifluoride etherate. The new protecting group conveys strong beta-selectivity with thiomannoside donors and undergoes a tin-mediated radical fragmentation to provide high yields of the synthetically challenging beta-rhamnopyranosides. The method is also applicable to the glucopyranosides when high alpha-selectivity is observed in the coupling reaction and alpha-quinovosides are formed selectively in the radical fragmentation step. In the galactopyranoside series, beta-glycosides are formed selectively on coupling to donors protected by the new system, but the radical fragmentation is unselective and gives mixtures of the 4- and 6-deoxy products. Variable-temperature NMR studies for the glycosylation step, which helped define an optimal protocol, are described.

References

Dec 31, 2002·Carbohydrate Research·Michael RammMatthias Hamburger
Feb 24, 2005·Journal of the American Chemical Society·Emiliano BediniCarlo Unverzagt

❮ Previous
Next ❯

Citations

Apr 29, 2006·Carbohydrate Research·David Crich, Mitesh Patel
Feb 7, 2018·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Alexandra N ZakharovaMads H Clausen
Dec 13, 2006·Angewandte Chemie·Aurore ServaisMax Malacria
Jan 29, 2009·Angewandte Chemie·Xiangming Zhu, Richard R Schmidt
Jan 1, 2015·Beilstein Journal of Organic Chemistry·Pintu Kumar Mandal
Apr 10, 2020·Organic & Biomolecular Chemistry·Diksha Rai, Suvarn S Kulkarni
Dec 6, 2017·Chemistry : a European Journal·Mary M JackmanSteven L Castle
May 23, 2009·The Journal of Organic Chemistry·Yu OnozakiKazuhiko Orito
Apr 18, 2009·The Journal of Organic Chemistry·A Fernández-MateosR Rubio González
Jan 23, 2013·The Journal of Organic Chemistry·Tobias Gylling FrihedChristian Marcus Pedersen
Apr 30, 2015·Chemical Reviews·Tobias Gylling FrihedChristian Marcus Pedersen
Oct 30, 2018·The Journal of Organic Chemistry·Takashi KanamoriHideya Yuasa
Apr 10, 2013·The Journal of Organic Chemistry·Naoki MichihataHidetoshi Yamada
Aug 19, 2007·Journal of the American Chemical Society·Toshiki NokamiJun-ichi Yoshida
Jan 12, 2022·Organic & Biomolecular Chemistry·Carla Marino, Andrea V Bordoni

❮ Previous
Next ❯

Related Concepts

Trending Feeds

COVID-19

Coronaviruses encompass a large family of viruses that cause the common cold as well as more serious diseases, such as the ongoing outbreak of coronavirus disease 2019 (COVID-19; formally known as 2019-nCoV). Coronaviruses can spread from animals to humans; symptoms include fever, cough, shortness of breath, and breathing difficulties; in more severe cases, infection can lead to death. This feed covers recent research on COVID-19.

Blastomycosis

Blastomycosis fungal infections spread through inhaling Blastomyces dermatitidis spores. Discover the latest research on blastomycosis fungal infections here.

Nuclear Pore Complex in ALS/FTD

Alterations in nucleocytoplasmic transport, controlled by the nuclear pore complex, may be involved in the pathomechanism underlying multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis and Frontotemporal Dementia. Here is the latest research on the nuclear pore complex in ALS and FTD.

Applications of Molecular Barcoding

The concept of molecular barcoding is that each original DNA or RNA molecule is attached to a unique sequence barcode. Sequence reads having different barcodes represent different original molecules, while sequence reads having the same barcode are results of PCR duplication from one original molecule. Discover the latest research on molecular barcoding here.

Chronic Fatigue Syndrome

Chronic fatigue syndrome is a disease characterized by unexplained disabling fatigue; the pathology of which is incompletely understood. Discover the latest research on chronic fatigue syndrome here.

Evolution of Pluripotency

Pluripotency refers to the ability of a cell to develop into three primary germ cell layers of the embryo. This feed focuses on the mechanisms that underlie the evolution of pluripotency. Here is the latest research.

Position Effect Variegation

Position Effect Variagation occurs when a gene is inactivated due to its positioning near heterochromatic regions within a chromosome. Discover the latest research on Position Effect Variagation here.

STING Receptor Agonists

Stimulator of IFN genes (STING) are a group of transmembrane proteins that are involved in the induction of type I interferon that is important in the innate immune response. The stimulation of STING has been an active area of research in the treatment of cancer and infectious diseases. Here is the latest research on STING receptor agonists.

Microbicide

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections. Here is the latest research on microbicides.

© 2022 Meta ULC. All rights reserved