Juntae Mo

Platinum-catalyzed intramolecular hydroarylation of allenyl arenes: efficient synthesis of 1,4-dihydronaphthalenes.

An efficient synthetic method of 1,4-dihydronaphthalenes having various alkyl groups on the 4-position and/or ethoxycarbonyl group on the 2-position through selective intramolecular Pt-catalyzed 6-endo cyclohydroarylation of ethyl 2-benzyl-2,3-alkadienoates was developed. The present method could be further extended to two-fold Pt-catalyzed 6-endo and 7-endo cyclizations.

Oxidative ortho-alkenylation of arylphosphine oxides by rhodium-catalyzed C–H bond twofold cleavage

An efficient Rh-catalyed oxidative ortho-alkenylation is reported from the reaction of arylphosphine oxides with activated and non-activated alkenes as well. The developed method is characterized by high selectivity, a wide substrate scope, and an excellent functional group tolerance.

Gold-Catalyzed Sequential Alkyne Activation for the Synthesis of 4,6-Disubstituted Phosphorus 2-Pyrones

Tandem gold-catalyzed addition of alkynyl phosphonic acid monoethyl esters to terminal alkynes and cyclization were developed for the synthesis of 4,6-disubstituted phosphorus 2-pyrones in one reaction vessel based on the concept of sequential alkyne activation. Alkynyl enol phosphonates were selectively obtained through the gold-catalyzed addition reaction in the presence of a catalytic amount of triethylamine. Also, gold-catalyzed cyclization of alkynyl enol phosphonates was successful in giving a variety of 4,6-disubstituted phosphorus 2-pyrones.

Preparation of ethyl 2-aryl 2,3-alkadienoates via palladium-catalyzed selective cross-coupling reactions.

Pd-catalyzed cross-coupling reactions of aryl iodides containing not only an electron-donating group but also an electron-withdrawing group on the aryl ring with organoindium reagents generated in situ from indium and ethyl 4-bromo-2-alkynoates produced selectively ethyl 2-aryl-2,3-alkadienoates in good yield.

Palladium‐Catalyzed Allyl Cross‐Coupling Reactions with In Situ Generated Organoindium Reagents

Inter- and intramolecular palladium-catalyzed allyl cross-coupling reactions, using allylindium generated in situ from allyl halides and indium, is demonstrated. Allylindium compounds may be effective nucleophilic coupling partners in palladium-catalyzed cross-coupling reactions. A variety of allyl halides, such as allyl iodide, allyl bromide, crotyl bromide, prenyl bromide, geranyl bromide, and 3-bromocyclohexene afforded the allylic cross-coupling products in good to excellent yields. Stereochemistry of the double bond is retained in the allylic cross-coupling reactions. Electrophilic cross-coupling partners, such as aryl and vinyl halides, dibromoolefin, alkynyl iodide, and aryl and vinyl triflates participate in these reactions. The presence of various substituents, such as n-butyl, ketal, acetyl, ethoxycarbonyl, nitrile, N-phenylamido, nitro, and chloride groups on the aromatic ring of electrophilic coupling partners showed little effect on the efficiency of the reactions. The present conditions work equally well for not only intermolecular but also intramolecular palladium-catalyzed cross-coupling reactions. These methods provide an efficient synthetic method for the introduction of an allyl group, which can be easily further functionalized to afford an sp(2)- and sp-hybridized carbon. The present method complements existing synthetic methods as a result of advantageous features such as easy preparation and handling, thermal stability, high reactivity and selectivity, operational simplicity, and low toxicity of allylindium reagents.

ICl-Mediated Intramolecular Twofold Iodoarylation of Diynes and Diynyl Diethers and Amines: Synthesis of Bis(2H-hydronaphthalene and chromene) and 2H-Quinoline Bearing an Alkenyl Iodide Moiety

Electrophilic intramolecular twofold iodoarylation was developed from the reaction of diynes and diynyl diethers and amines with iodine monochloride under mild conditions, which produced bis(2H-hydronaphthalene and chromene) and 2H-quinoline bearing an alkenyl iodide moiety in good to excellent yields. These compounds underwent Pd-catalyzed cross-coupling reactions with arylboronic acid and indium tris(arylthiolate) to produce the functionalized styrene derivatives.

Tandem Diels−Alder/Cross-Coupling Reactions of Generated in Situ Organoindium Reagents in a One-Pot Process

Tandem Diels-Alder/cross-coupling reactions with organoindium reagents generated in situ from 1-bromo-2,3-butadiene and indium were developed in a one-pot process. [4 + 2] Cycloaddition reactions using organoindium reagents and subsequent Pd-catalyzed cross-coupling reactions provided the rapid synthesis of six-membered carbocycles starting from 1-bromo-2,3-butadiene.