Alkyl S-Glycosides As Electroactive Glycosyl Donors: Study of the Effect of the Steric and Electronic Properties of the Aglycone and Protective Groups over the Oxidation Potential

AbstractSilicon has been used in carbohydrate chemistry for half a century, but mostly as a protective group for sugar alcohols. Recently, the use of silicon has expanded to functionalization via C–H activation, conformational arming of glycosyl donors, and conformational alteration of carbohydrates. Silicon has proven useful as more than a protective group and during the last one and a half decades we have demonstrated how it influences both the reactivity of glycosyl donors and stereochemical outcome of glycosylations. Silicon can also be attached directly to the sugar C-backbone, which has even more pronounced effects on the chemistry and properties of the molecules. In this Account, we will give a tour through our work involving silicon and carbohydrates.1 Introduction2 Conformational Arming of Glycosyl Donors with Silyl Groups3 Silyl Protective Groups for Tethering Glycosyl Donors4. Si–C Glycosides via C–H Activation4.1 C–H Activation and Oxidation of Methyl 6-Deoxy-l-glycosides4.2 Synthesis of All Eight 6-Deoxy-l-sugars4.3 Synthesis of All Eight l-Sugars by C–H Activation4.4 Modification of the Oxasilolane Ring5 C–Si in Glycosyl Donors – Activating or Not?6 Si–C-Substituted Pyranosides7 Perspective

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Chemical synthesis of diglucosyl diacylglycerols utilizing glycosyl donors with stereodirecting cyclic silyl protective groups

Carbohydrate Research ◽

10.1016/j.carres.2019.107748 ◽

2019 ◽

Vol 483 ◽

pp. 107748 ◽

Cited By ~ 1

Author(s):

Koichi Takato ◽

Motoki Kurita ◽

Nahoko Yagami ◽

Hide-Nori Tanaka ◽

Hiromune Ando ◽

...

Keyword(s):

Chemical Synthesis ◽

Protective Groups ◽

Glycosyl Donors

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Silyl-protective groups influencing the reactivity and selectivity in glycosylations

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.13.12 ◽

2017 ◽

Vol 13 ◽

pp. 93-105 ◽

Cited By ~ 29

Author(s):

Mikael Bols ◽

Christian Marcus Pedersen

Keyword(s):

Organic Chemistry ◽

Protective Group ◽

Carbohydrate Chemistry ◽

Protective Groups ◽

Silyl Groups ◽

High Stereoselectivity ◽

Glycosyl Donors

Silyl groups such as TBDPS, TBDMS, TIPS or TMS are well-known and widely used alcohol protective groups in organic chemistry. Cyclic silylene protective groups are also becoming increasingly popular. In carbohydrate chemistry silyl protective groups have frequently been used primarily as an orthogonal protective group to the more commonly used acyl and benzyl protective groups. However, silyl protective groups have significantly different electronic and steric requirements than acyl and alkyl protective groups, which particularly becomes important when two or more neighboring alcohols are silyl protected. Within the last decade polysilylated glycosyl donors have been found to have unusual properties such as high (or low) reactivity or high stereoselectivity. This mini review will summarize these findings.

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Ruthenium bistridentate complexes with non-symmetrical hexahydro-pyrimidopyrimidine ligands: a structural and theoretical investigation of their optical and electrochemical properties

Dalton Transactions ◽

10.1039/c6dt02408d ◽

2016 ◽

Vol 45 (31) ◽

pp. 12507-12517 ◽

Cited By ~ 6

Author(s):

Baptiste Laramée-Milette ◽

Garry S. Hanan

Keyword(s):

Electrochemical Properties ◽

Electronic Properties ◽

Theoretical Investigation ◽

Metal Ion ◽

Oxidation Potential ◽

Tridentate Ligands ◽

Optical And Electronic Properties ◽

Ru Complexes

The optical and electronic properties of six Ru complexes with non-symmetrical tridentate ligands have been investigated and, as corroborated by electrochemical data, the presence of the hpp ligand strongly affects the oxidation potential of the metal ion.

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The oxidation of Inconel alloy MA754 at low oxidation potential

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074884 ◽

1983 ◽

Vol 41 ◽

pp. 218-219

Author(s):

D. N. Braski ◽

P. D. Goodell ◽

J. V. Cathcart ◽

R. H. Kane

Keyword(s):

Surface Layer ◽

Oxidation Potential ◽

Metal Interface ◽

Elevated Temperature Strength ◽

Surface Conditions ◽

Inconel Alloy ◽

Inco Alloy ◽

Resistance To Oxidation ◽

Oxide Particles ◽

Cold Worked

It has been known for some time that the addition of small oxide particles to an 80 Ni—20 Cr alloy not only increases its elevated-temperature strength, but also markedly improves its resistance to oxidation. The mechanism by which the oxide dispersoid enhances the oxidation resistance is being studied collaboratively by ORNL and INCO Alloy Products Company.Initial experiments were performed using INCONEL alloy MA754, which is nominally: 78 Ni, 20 Cr, 0.05 C, 0.3 Al, 0.5 Ti, 1.0 Fe, and 0.6 Y2O3 (wt %).Small disks (3 mm diam × 0.38 mm thick) were cut from MA754 plate stock and prepared with two different surface conditions. The first was prepared by mechanically polishing one side of a disk through 0.5 μm diamond on a syntron polisher while the second used an additional sulfuric acid-methanol electropolishing treatment to remove the cold-worked surface layer. Disks having both surface treatments were oxidized in a radiantly heated furnace for 30 s at 1000°C. Three different environments were investigated: hydrogen with nominal dew points of 0°C, —25°C, and —55°C. The oxide particles and films were examined in TEM by using extraction replicas (carbon) and by backpolishing to the oxide/metal interface. The particles were analyzed by EDS and SAD.

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Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176149 ◽

1990 ◽

Vol 48 (4) ◽

pp. 602-603

Author(s):

J.M. Bonar ◽

R. Hull ◽

R. Malik ◽

R. Ryan ◽

J.F. Walker

Keyword(s):

Band Gap ◽

Electronic Properties ◽

Gaas Substrate ◽

Critical Thickness ◽

Lattice Mismatch ◽

Band Offset ◽

Misfit Dislocations ◽

Gaas Substrates ◽

Gaas Structure ◽

Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

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