이영호 교수

We developed a conceptually new synthetic strategy which exploits the stereochemical information of labile acyclic N,O-acetals. The key to this strategy, chemo- and stereoselective synthesis of N,O-acetals, was achieved by the Pd-catalyzed addition of sulfonyl-protected homopropargylic amines to alkoxyallene. The N,O-acetals generated in this way were combined with Au-catalyzed cycloisomerization to give an access to 2,6-disubstituted piperidines with stereochemical flexibility.

A ligand-directed metal-catalyzed asymmetric intermolecular hydroalkoxylation of alkoxyallene is reported. Combined with ring-closing-metathesis, this reaction offers a new atom-efficient synthetic method toward various cyclic acetals with elaborate anomeric control. Synthetic utility of the reaction was demonstrated by the atom-efficient and stereodivergent access to various mono- and disaccharides.

A new gold(I)-catalyzed cycloisomerization to access highly substituted piperidines has been developed. By combining a conceptually new way of generating iminium ions using cationic gold(I) complexes and an efficient cyclization reaction that can minimize a potentially competing aza-Cope rearrangement, the proposed reaction successfully circumvents a long-standing problem in the classical aza-Prins reaction. Synthetic utility of the catalytic reaction was demonstrated by a synthesis of optically

Shine a light: A fluorescent light-induced synthetic method for the title compounds has been developed and the chemoselective nature of the reaction is highlighted by the observation of the cis/trans isomers of various N-unsubstituted imines. The synthetic utility of this method is demonstrated by the one-pot imine formation/asymmetric allylation sequence of benzyl azide catalyzed by 1. (Ipc=isopinocampheyl). Detailed facts of importance to specialist readers are published as ”Supporting Informa

Aromatic N-H ketimines were in situ generated from various benzylic azides by ruthenium catalysis for the subsequent Rh-catalyzed annulation reaction with alkynes to give the corresponding isoquinolines. In contrast to conventional synthetic methods for aromatic N-H ketimines, our protocol works under mild and neutral conditions, which enabled the synthesis of isoquinolines having various functionalities such as carbonyl, ester, alkenyl, and ether groups. In addition, the imidates generated from

In control: A new synthetic strategy towards cyclic amines was developed and exploits a stereodefined cyclic N,O-acetal as the key stereocontrol and diversity-generating element. The cyclic N,O-acetal was prepared from the sequential asymmetric hydroamination of an alkoxyallene with the chiral ligand L*, and ring-closing metathesis. The stereochemical integrity of the labile N,O-acetal was conserved in all catalytic transformations. Detailed facts of importance to specialist readers are publishe

A new palladium-catalyzed asymmetric addition reaction of indoles to alkoxyallenes is reported. Remarkably, the reaction showed complete regioselectivity toward the nitrogen. A new mechanism distinct from that of conventional π-allyl chemistry is proposed to explain this unique selectivity. The utility of the reaction is demonstrated by highly efficient and flexible synthesis of N-glycosylindoles.

A de novo synthetic method towards apiose, a structurally unusual furanose, is reported. The key feature is sequential metal catalysis consisting of the palladium-catalyzed asymmetric intermolecular hydroalkoxylation of an alkoxyallene and subsequent ring-closing metathesis (RCM). This strategy enabled the efficient synthesis of various apiose-containing disaccharides and a unique convergent synthesis of trisaccharides.

Abstract An efficient method for the preparation of diaryl selenides, which are important in biology and materials science, is described. Specifically, the development of highly substituted phenanthrenyl phenyl selenides 4 and 6 by metal‐catalyzed cyclization of o ‐phenylarylalkynes species 1 was successfully performed. The selectivity for 9‐ and 10‐selenyl phenanthrenes was perfectly controlled by indium(III) and gold(I) catalysts, and the reactions proceed through different pathways. For the I

Gold cycle redesigned: By utilizing the alkynophilic effect of gold(I) complexes, a new method for the synthesis of highly substituted cis-2,6-tetrahydropyranones was developed, which represents a catalytic surrogate of the Petasis–Ferrier rearrangement (see scheme). Of particular interest is the unique effect the phosphine ligand has on the diastereoselectivity of the alkyl groups at the 2- and 6-positions. Detailed facts of importance to specialist readers are published as ”Supporting Informat

Gold schließt den Ring: Eine neue Gold(I)-katalysierte Cycloisomerisierung wandelt einfach aufgebaute 3-Methoxy-1,6-enine durch eine Cyclisierung und [3,3]-sigmatrope Umlagerung in 1-Methoxy-1,4-cycloheptadiene um (siehe Schema). Die Reaktion läuft unter milden Bedingungen ab, und die Produkte können leicht zu Cyclohept-4-en-1-onen umgesetzt werden.

Catalytic asymmetric synthesis of N-heterocyclic glycosides free of protecting and directing groups is reported. The key reaction is highlighted by the atom-efficient and regioselective addition of unprotected pyrimidines to highly functionalized alkoxyallene. Numerous acyclic and cyclic N-heterocyclic glycosides are accessed with minimal formation of organic byproducts. The synthetic utility of the reaction is demonstrated by the first catalytic asymmetric synthesis of anticancer pharmaceutical

A de novo first collective total synthesis of 11-deoxylandomycins is reported. A signature step is featured by the Pd-catalyzed asymmetric addition of alcohol to ene-alkoxyallenes that assembles oligomeric 2,3,6-trideoxyoligosaccharides. The unique feature of the protocol is illustrated by a flexible access to various natural 11-deoxylandomycins as well as non-natural analogues.

A de novo synthetic strategy for the production of oligosaccharides containing 2,3,6-trideoxypyranoglycoside is reported. The key event is the Pd-catalyzed asymmetric diastereoselective hydroalkoxylation of ene-alkoxyallene-linked glycosidic fragments. The utility of this approach was demonstrated by the activation-free, stereodivergent, and convergent synthesis of various 2-deoxyoligosaccharides, as well as their aglycon conjugates.

The first gold-catalyzed intermolecular coupling of alkynoates and allylic ethers invoking alkoxy addition and [3,3]-sigmatropic rearrangement as the key mechanism has been developed. Remarkably, the reaction showed complete chemoselectivity toward the pathway initiated by the alkoxy addition to alkynes. This unprecedented reactivity led to a new access to diversely substituted β-alkoxyacrylates in a highly efficient manner.