이철범 교수

A mild, palladium(II)-catalyzed ring-forming aminoacetoxylation of alkenes is described. Treatment of a range of nitrogen nucleophiles with catalytic palladium(II) in the presence of PhI(OAc)2 as oxidant resulted in alkene aminoacetoxylation, affording a variety of nitrogen-containing heterocycles. Our studies indicate the possibility for high levels of reaction regio- and stereocontrol. It appears that this is a stereoselective trans alkene difunctionalization and thus a useful alternative to r

A photo opportunity: A visible-light-excited iridium catalyst delivers electrons from an amine to an organohalide. The electron transfer then induces reductive scission of the carbon–halogen bond, generating the corresponding alkyl, alkenyl, and aryl radical that can undergo cyclization and hydrodehalogenation reactions. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made ava

With their mechanistic novelty and various modalities of reactivity, transition metal unsaturated carbene (alkenylidene) complexes have emerged as versatile intermediates for new reaction discovery. In particular, the past decade has witnessed remarkable advances in the chemistry of metal vinylidenes and allenylidenes, leading to the evolution of a diverse array of new catalytic transformations that are mechanistically distinct from those developed in the previous two decades. This review aims t

This chapter contains sections titled: Introduction Fundamental Elements of Enantioselective Allylic Alkylation Palladium-Catalyzed Enantioselective Allylation Enantioselective Allylation by Other Metals Conclusions References

A highly stereoselective palladium-catalyzed O-glycosylation reaction is described. The reaction of a glycal 3-acetate or carbonate with the zinc(II) alkoxide of acceptors establishes the glycosidic linkage under palladium catalysis to give rise to disaccharides as the product in good yields and with high stereoselectivity. In contrast to the Lewis acid mediated Ferrier procedure, the anomeric stereochemistry of this reaction is controlled by the employed ligand. Whereas the use of a complex of

Herein we report a highly efficient method for nickel-catalyzed C-N bond formation between sulfonamides and aryl electrophiles. This technology provides generic access to a broad range of N-aryl and N-heteroaryl sulfonamide motifs, which are widely represented in drug discovery. Initial mechanistic studies suggest an energy-transfer mechanism wherein C-N bond reductive elimination occurs from a triplet excited Ni^II complex. Late-stage sulfonamidation in the synthesis of a pharmacologi

The C-H imidation of arenes and heteroarenes has been achieved via visible light induced photocatalysis. In the presence of an iridium(III) photoredox catalyst, the reaction of aromatic substrates with N-chlorophthalimide furnishes the N-aryl products at room temperature through a nitrogen-centered radical mediated aromatic substitution.

The equivalent of an asymmetric addition to a carbonyl group with a stabilized anion is accomplished by discriminating between the enantiotopic C-O single bonds of a gem-diacetate. In this way, enantioselective total syntheses of two antifugal agents, sphingofungins E and F, have been accomplished. The synthetic strategy is based on a series of catalytic processes whereby all of the chiral centers are created with high stereoselectivities. The first two stereocenters are introduced by an asymmet

Bei Licht betrachtet: Ein durch sichtbares Licht angeregter Iridiumkatalysator überträgt Elektronen von einem Amin auf ein Organohalogenid. Der Elektronentransfer löst daraufhin die reduktive Spaltung der Kohlenstoff-Halogen-Bindung aus und erzeugt das entsprechende Alkyl-, Alkenyl- oder Arylradikal, das Cyclisierungs- und Hydrodehalogenierungsreaktionen eingehen kann. DIPEA=N,N-Diisopropylethylamin.

Cyanine (Cy) dyes are among the most useful organic fluorophores that have found a wide range of applications in single-molecule and super-resolution imaging as well as in other biophysical studies. However, recent observations that blueshifted derivatives of Cy dyes are formed via photoconversion have raised concerns as to the potential artifacts in multicolor imaging. Here, we report the mechanism for the photoconversion of Cy5 to Cy3 that occurs upon photoexcitation during fluorescent imaging

A gem of a couple: The title reaction of terminal alkynes with O and N nucleophiles proceeds in the presence of [{Rh(cod)Cl}2], P(4-FC6H4)3, and 4-picoline N-oxide. Alcohols, amines, and water add to the terminal alkynes to give esters, amides, and carboxylic acids, respectively. The reaction involves formation of a rhodium vinylidene, oxidation to a ketene by oxygen transfer, and nucleophilic addition.

An efficient protocol for the modular synthesis of sulfones and sulfonyl derivatives has been developed utilizing sodium <i>tert</i>-butyldimethylsilyloxymethanesulfinate (TBSOMS-Na) as a sulfoxylate (SO₂ ^2-) equivalent. TBSOMS-Na, easily prepared from the commercial reagents Rongalite™ and TBSCl, serves as a potent nucleophile in <i>S</i>-alkylation and Cu-catalyzed <i>S</i>-arylation reactions with alkyl and aryl electrophiles. The sulfone products thus obtained can under

Transition metal-mediated catalysis routinely enables substrates of multiple π-systems to be efficiently coupled with various carbon nucleophiles along with simultaneous ring formation. This transformation, however, remains unexplored in connection with pericyclic processes. Reported here is a protocol for cycloalkene synthesis based on the merger of rhodium catalysis and a retro-ene reaction. The approach allows alkyne-tethered hydrazones and organoboronic acids to undergo a cascade of addition

Und Sauerstoff dazu: In Gegenwart von [{Rh(cod)Cl}2], P(4-FC6H4)3 und 4-Picolin-N-oxid reagieren terminale Alkine mit O- und N-Nukleophilen (Alkoholen, Aminen und Wasser) zu Estern, Amiden und Carbonsäuren. Die Reaktion verläuft über die Bildung eines Rhodiumvinylidenkomplexes, Oxidation zum Keten durch Sauerstofftransfer und nukleophile Addition. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and ma