ADVERTISEMENT RETURN TO ISSUEPREVLetterNEXTHighly Efficient Synthesis of Phenols by Copper-Catalyzed Oxidative Hydroxylation Arylboronic Acids at Room Temperature in WaterJimin Xu, Xinyan Wang*, Changwei Shao, Deyong Su, Guolin Cheng, and Yuefei Hu*View Author Information Department Chemistry, Tsinghua University, Beijing 100084, P. R. China[email protected]; [email protected]Cite this: Org. Lett. 2010, 12, 9, 1964–1967Publication Date (Web):April 8, 2010Publication History Received15...

An extremely convenient method for deprotection of acetals and ketals catalyzed by molecular iodine (10 mol %) in acetone is reported. The protocol achieved the acyclic or cyclic O,O-acetals O,O-ketals excellent yields within a few minutes under neutral conditions. double bond, hydroxyl group, acetate group remained unchanged, highly acid-sensitive furyl, tert-butyl ethers, ketone-oxime stayed intact these

In this article, we proved that all three key steps in the catalytic cycle of CuAAC can proceed presence carboxylic acids and latter two be promoted significantly by acids. Benzoic acid showed best promotion activity, with strong chelating ability to Cu(I) ion could not serve for purpose. Thus, first acid-promoted highly efficient was established.

In this novel acid-base jointly promoted CuAAC, the combination of CuI/DIPEA/HOAc was developed as a highly efficient catalytic system. The functions DIPEA and HOAc have been assigned, recognized to accelerate conversions C-Cu bond-containing intermediates buffer basicity DIPEA. As result, all drawbacks occurring in popular system CuI/NR(3) were overcome easily.

A novel silver-catalyzed decarboxylative acylation of α-oxo-carboxylic acids was developed, by which various 3-acyl quinoxalin-2(1<italic>H</italic>)-ones were synthesized direct C–H bond quinoxalin-2(1<italic>H</italic>)-ones.

Ammonia (NH

Abstract In this article, the structurally well‐defined dinuclear complex copper(I) acetate was studied in detail and developed as a highly practical efficient catalyst for copper(I)‐catalyzed azide‐alkyne cycloaddition. The “bare” phenylethynylcopper(I) (i.e., with no exogeneous ligands) isolated an intermediate, which can be converted into active catalytic species by treatment acetic acid ( situ produced reaction) to efficiently catalyze cycloaddition under mild conditions.

Total syntheses of enantiopure alkaloidal natural products (2S,6R)-dihydropinidine (as hydrochloride) and (2S,6R)-isosolenopsins hydrochlorides) were achieved in four steps 80−82% total yields by using a synthetic strategy the formation-cleavage 1,3-oxazinane. (S)-Betti base was proved to be an excellent chiral auxiliary novel Pd/C catalyzed N-debenzylation straightforward amine hydrochloride developed presence CH2Cl2.

Abstract In lower nitrile solvents, the N ‐arylation of azoles with aryl halides was achieved efficiently in presence copper powder without any additional ligands. Thus, first type monodentate ligand‐mediated, “ligand‐free‐like” copper‐catalyzed procedure established.

A facile Pd-catalyzed conversion of aryl and vinyl triflates to halides (bromides chlorides) is described. This method allows convenient access a variety aryl, heteroaryl, in good excellent yields with greatly simplified conditions relative our previous report.

A general method for the preparation of enantiopure 2-alkene- or 2-alkyne-containing chain substituted piperidines was established by using nonracemic Betti base as a chiral auxiliary. The key step is that auxiliary residue removed novel base-catalyzed N-debenzylation via formation o-quinone methide mechanism in stead traditional hydrogenolysis, which alkene alkyne groups survived. By this method, ten were prepared on gram scale within few hours. To demonstrate efficiency and versatility...

A highly reactive intermediate N-sulfonyl acetylketenimine was generated from a 3-butyn-2-one participating CuAAC/ring-opening method. Its high reactivity due to bearing two EWGs allowed us offer the first example of reaction between ketenimine and amide synthesize amidines efficiently.

An efficient kinetic resolution of racemic Betti base with L-(+)-tartaric acid in acetone was developed based on a novel enantioselective N,O-deketalization, by which the enantiopure R- and S-enantiomers were obtained as corresponding N,O-ketal compound salt acid, respectively, excellent yields practically foolproof operation.

Total synthesis of tropane alkaloids (−)-cocaine and (−)-ferruginine were accomplished in nine steps each 55% 46% overall yields, respectively, starting from the known Betti base derivative (+)-(7aR,10R,12S)-10-(1H-benzotriazol-1-yl)-7a,8,9,10-tetrahydro-12-phenyl-12H-naphtho[1,2-e]pyrrolo[2,1-b][1,3]oxazine. In this novel route, RCM reaction 1,3-dipolar cycloaddition employed as key for enantioselective construction skeleton regioselective introduction 3-bromo-2-isoxazoline ring masked...

A highly efficient copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) of 6-substituted tetrazolo[1,5-a]pyridines was developed for the preparation 1-(pyridin-2-yl)-1,2,3-triazoles by simply using copper(I) acetate as a catalyst. The in situ formed HOAc played important dual roles and an activation 2-azidopyridine–copper(I) complex observed.

A novel preparation of N-substituted pyrrole-2-carboxylates has been developed based upon 1,3-dipolar cycloaddition and a conventional hydrogenolysis. By using this method as the key step, total syntheses natural alkaloids (−)-hanishin, (−)-longmide B, B methyl ester were accomplished in highest overall yields, respectively.

A tandem synthesis of 3-halo-5-substituted isoxazoles has been developed from 1-copper(I) alkynes and dihaloformaldoximes under base-free conditions. Thus, 1,3-dipolar cycloaddition all its drawbacks can now be avoided completely.

A novel tandem reaction of 1-copper(I) alkynes with azides (cycloaddition) and then NCS (electrophilic substitution) was developed as an efficient method for the synthesis 1,4,5-trisubstituted 5-chloro-1,2,3-triazoles. The offers a rare example that organometallic substrate does not involve in reactivity metal-carbon bond first step.

A sensor was developed based on the quenching effect of Cu²⁺ PPESO₃ and hydrolysis ATP by ALP.

Abstract Let's twist again! Remarkable broad and twisted ribbons were generated from the self‐assembly of oligo( p ‐ phenylene ethylene) (OPE) bearing dimeric deoxycholic acid pendant groups (see graphic). Varying bile led to nanostructures with drastically different morphologies. The distinctive aggregate shapes these steroid–OPE conjugates are attributed subtle differences in their molecular structures. magnified image A series novel ‐phenylene ethynylene) derivatives cholic (OPE1), (OPE2)...