Youqian Deng

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The use of ligands to tune the reactivity and selectivity of transition metal catalysts for C(sp(3))-H bond functionalization is a central challenge in synthetic organic chemistry. Herein, we report a rare example of catalyst-controlled C(sp(3))-H arylation using pyridine and quinoline derivatives: The former promotes exclusive monoarylation, whereas the(More)
Vinylallenes or cross-conjugated trienes are obtained selectively in the title reaction. Two possible mechanisms are suggested to rationalize the formation of the different types of products. Control experiments indicate that p-benzoquinone (BQ) plays an important role as a ligand in addition to its role as an oxidant. E=CO(2)Me.
Palladium-catalyzed oxidative carbon-carbon bond-forming annulations, that is, carbocyclization reactions, have recently emerged as efficient and atom-economical routes to carbo- and heterocycles, whereby less functionalized substrates and fewer synthetic steps are needed to obtain a target molecule compared with traditional non-oxidative carbon-carbon(More)
An allene to allene protocol for the synthesis of beta-allenyl butenolides in moderate to high yields from 2,3-allenoic acids and propargylic carbonates catalyzed by Pd(OAc)2-TFP has been developed; the products were applied successfully to the Diels-Alder reaction with electron-deficient alkynes to afford polysubstituted benzene derivatives with an(More)
3-(Methoxycarbonyl)-2-halo-1,3(Z)-dienes were prepared highly stereoselectively via SN2'-type addition-elimination reactions of 3-(methoxycarbonyl)-1,2-allen-4-ols with MX. These products may easily undergo Negishi or Sonogashira coupling reactions to yield a series of stereodefined polysubstituted (E)-1,3-dienes.
meta-C-H olefination of phenylacetic acid derivatives has been achieved using a commercially available nitrile-containing template. The identification of N-formyl-protected glycine as the ligand (Formyl-Gly-OH) was crucial for the development of this reaction. Versatility of the template approach in accommodating macrocyclopalladation processes with(More)
A palladium(II)-catalyzed tandem double-cyclization reaction of 1,omega-bisallenols was developed to form 2,5-dihydrofuran-fused bicyclic skeletons. With "unsymmetric" substrates, the reaction may also be realized with one hydroxyl group being protected as the acetate. Optically active bicyclic products were prepared by applying the Novozym-435 catalyzed(More)
Palladium(II)-catalyzed oxidative carbocyclizations represent an important class of reactions, which have provided powerful and atom-economical approaches to carboand heterocycles. In particular, oxidative carbocyclization strategies have been efficiently applied to total synthesis. As a continuation of our research on the palladium-catalyzed oxidative(More)
Transition-metal-catalyzed dimeric coupling-cyclization reactions of two different 2,3-allenols afforded 4-(1',3'-dien-2'-yl)-2,5-dihydrofuran derivatives 3. 2-Substituted 2,3-allenols 1 cyclized to form the 2,5-dihydrofuran ring, whereas the 2-unsubstituted 2,3-allenols 2 provided the 1,3-diene unit at the 4-position. The reaction is proposed to proceed(More)