The mean size of the gold (Au) core in the synthesis of dodecanethiolate-stabilized Au cluster compounds can be finely adjusted by choice of the Au:dodecanethiolate ratio and the temperature and rate at which the reduction is conducted. The Au clusters have been examined with a large number of independent analytical tools, producing a remarkably consistent picture of these materials. Average cluster and core dimensions, as ascertained by 1H NMR line broadening, high-resolution transmission electron microscopy, small-angle X-ray scattering, and thermogravimetric analysis, vary between diameters of 1.5 and 5.2 nm (∼110−4800 Au atoms/core). The electronic properties of the Au core were examined by UV/vis and X-ray photoelectron spectroscopy; the core appears to remain largely metallic in nature even at the smallest core sizes examined. The alkanethiolate monolayer stabilizing the Au core ranges with core size from ∼53 to nearly 520 ligands/core, and was probed by Fourier transform infrared spectroscopy, diff...

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Alkanethiolate Gold Cluster Molecules with Core Diameters from 1.5 to 5.2 nm: Core and Monolayer Properties as a Function of Core Size

Introduction Cationic domino reactions Anionic domino reactions Radical domino reactions Pericyclic domino reactions Photochemically induced domino processes Transition metal catalysis Domino reactions initiated by oxidation or reduction Enzymes in domino reactions Multicomponent reactions Special techniques in domino reactions

Domino Reactions in Organic Synthesis

10. Patented Literature 2616 10.1. Esterification 2616 10.2. Ether Formation 2619 10.2.1. Etherification without Cyclization 2619 10.2.2. Etherification with Cyclization 2624 10.3. N-Alkylation 2625 10.4. Other Reactions 2627 11. Summary and Outlook 2628 12. Note Added in Proof 2628 13. Abbreviations Used in This Review 2629 14. Acknowledgments 2629 15. Supporting Information Available 2630 16. References 2630

Mitsunobu and Related Reactions: Advances and Applications

Relative energetics of fragmentation of protonated peptides are investigated by using electrospray ionization/surface-induced dissociation (ESI/SID) tandem mass spectrometry. ESI/SID fragmentation efficiency curves (percent fragmentation versus laboratory collision energy) are presented for 20 oligopeptides and are a measure of how easily a peptide fragments. The relative positions of the ESI/SID fragmentation efficiency curves depend on several parameters which include peptide composition (e.g., presence/absence of a basic amino acid residue) and peptide size. The ESI/SID fragmentation efficiency curves, in combination with quantum chemical calculations, provide a unique approach to substantiate and refine the mobile proton model for peptide fragmentation. Selected peptides are also investigated to further test and confirm the mobile proton model; these include doubly-protonated peptides and chemically-modified peptides (i.e., acetylated and fixed-charge derivatized peptides). Doubly-protonated peptides ...

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Influence of Peptide Composition, Gas-Phase Basicity, and Chemical Modification on Fragmentation Efficiency: Evidence for the Mobile Proton Model

The present review offers an overview of the current approaches for the photochemical and photocatalytic generation of reactive intermediates and their application in the formation of carbon–carbon bonds. Valuable synthetic targets are accessible, including arylation processes, formation of both carbo- and heterocycles, alpha- and beta-functionalization of carbonyls, and addition reactions onto double and triple bonds. According to the recent advancements in the field of visible/solar light catalysis, a significant part of the literature reported herein involves radical ions and radicals as key intermediates, with particular attention to the most recent examples. Synthetic application of carbenes, biradicals/radical pairs and carbocations have been also reported.

Carbon-Carbon Bond Forming Reactions via Photogenerated Intermediates.

Armed and disarmed n-pentenyl glycosides in saccharide couplings leading to oligosaccharides

Torsional effects in glycoside reactivity: saccharide couplings mediated by acetal protecting groups

Two New Orthogonal Amine-Protecting Groups that can be Cleaved under Mild or Neutral Conditions

N-Iodosuccinimide and trifluoromethanesulphonic acid provide a powerful source of Iodonium ion which allows ‘disarmed’ pent-4-enyl glycosides that normally respond sluggishly to lodonium dicollidine perchlorate, to react rapidly and to exhibit stereodirection via neighbouring group participation of C-2 esters.

Bert Fraser-Reid

Papers

Armed and disarmed n-pentenyl glycosides in saccharide couplings leading to oligosaccharides

Torsional effects in glycoside reactivity: saccharide couplings mediated by acetal protecting groups

Two New Orthogonal Amine-Protecting Groups that can be Cleaved under Mild or Neutral Conditions

Iodonium ion generated in situ from N-iodosuccinimide and trifluoromethanesulphonic acid promotes direct linkage of ‘disarmed’ pent-4-enyl glycosides

n-Pentenyl glycosides permit the chemospecific liberation of the anomeric center