Zinc mediated straightforward access to diacylpyrroles

In this article, we report the preparation of various 2,4- and 2,5-diacylpyrroles via two zinc-mediated acylation reactions of non-protected pyrroles.     

First selective lithiation of pyridylpiperazines: straightforward access to potent pharmacophores

The three isomers of pyridylpiperazines have been lithiated for the first time. The use of a superbase, an aminoalkoxide containing lithiating agent overcomes the chelating influence of the basic piperazine nitrogens, so that selective mono lithiation occurred alpha to pyridine nitrogen. This methodology offers a new access to diverse potent pharmacophores not easily prepared by other routes.     

Copper-catalyzed intramolecular C-N bond formation: a straightforward synthesis of benzimidazole derivatives in water

A straightforward, efficient, and more sustainable copper-catalyzed method has been developed for intramolecular N-arylation providing the benzimidazole ring system. With Cu(2)O (5 mol %) as the catalyst, DMEDA (10 mol %) as the ligand, and K(2)CO(3) as the base, this protocol was applied to synthesize a small library of benzimidazoles in high yields. Remarkably, the reaction was exclusively carried out in water, rendering the methodology highly valuable from both environmental and economical points of view.     

CO2 incorporation reaction using arynes: straightforward access to benzoxazinone

A zwitterion, generated from an aryne and an imine, has been demonstrated to serve as an excellent molecular scaffold for capturing CO2, which results in the straightforward formation of diverse benzoxazinones.     

Cross-coupling of highly pyramidalized alkenes: A straightforward access to functionalized tetrasecododecahedradienes

The synthesis and chemical trapping of a highly pyramidalized pentacyclo[6.4.0.0(2,10).0(3,7).0(4,9)]dodec-8-ene containing ketal functions is reported. Its cross-coupling reaction with 3, 7-dimethyltricyclo[3.3.0.0(3,7)]oct-1(5)-ene followed by a [2 + 2] retrocycloaddition reaction gives a straightforward access to functionalized tetrasecododecahedradienes.     

A straightforward access to pyrrolidine-based ligands for asymmetric synthesis

A straightforward and flexible method for the preparation of ligands based on the pyrrolidine scaffold is presented. The synthetic strategy involves a diastereoselective allylation of phenylglycinol-derived imines, followed by a cyclization promoted by a hydrozirconation/halogenation sequence. Enantioselectivities of up to 84% ee in the asymmetric allylic allylation were obtained using these ligands.     

Three-component coupling using arynes and DMF: straightforward access to coumarins via ortho-quinone methides

ortho-Quinone methides, arising from a formal [2+2] cycloaddition between arynes and DMF, were found to facilely undergo a [4+2] cycloaddition with ester enolates or ketenimine anions to produce diverse coumarins in a straightforward manner.     

Rhodium-catalyzed tandem conjugate addition-Mannich cyclization reaction: straightforward access to fully substituted tetrahydroquinolines

A new Rh(I)-catalyzed tandem conjugate addition-Mannich cyclization reaction of imine-substituted electron-deficient alkenes with arylboronic acids has been developed to afford 2,3,4-trisubstituted 1,2,3,4-tetrahydroquinolines. This is the first example involving imine group as a secondary electrophile in Rh(I)-catalyzed tandem reactions.     

A straightforward synthetic access to symmetrical glycosyl disulfides and biological evaluation thereof

Symmetrical glycosyl disulfides can be prepared within a few hours from per-O-acetylated precursors via a sequential approach entailing short reactions and no purification of any intermediate. The final thiolate-to-disulfide oxidation step is noticeably accelerated by low amounts of phenyl diselenide under air. Applicability of the strategy to non-saccharidic symmetrical alkyl disulfides has also been examined. A preliminary assay of the cytotoxic activity of symmetrical 1,1'- disulfides was performed on two human tumor cell lines, and a noteworthy activity was recorded for a range of these synthetic compounds.     

A straightforward synthesis of indole and benzofuran derivatives

A new methodology for the synthesis of indole and benzofuran derivatives has been devised. The starting materials, ortho-substituted aryl diynes, have been easily converted into new unsaturated bis-indolyl and bis-benzofuran derivatives and into 2-ethynylindole and 2-ethynylbenzofuran. Both these products have been further elaborated into more complex unsaturated indole-benzofuran and bis-benzofuran derivatives.     

Three-component coupling using arynes and isocyanides: straightforward access to benzo-annulated nitrogen or oxygen heterocycles

A variety of aldehydes, ketones, benzoquinones, or sulfonylimines were found to couple with arynes and isocyanides, giving iminodihydroisobenzofuran or iminoisoindoline derivatives of structural diversity in a straightforward manner. Nucleophilic addition of isocyanides to arynes, a first step of the three-component coupling, was proved to be reversible by the reaction of an unsymmetrical aryne.     

Microwave-assisted aza-Prins reaction. Part 2: straightforward access to 2,6-disubstituted 1-azaadamantanes

Novel symmetrically and unsymmetrically disubstituted 1-azaadamantanes were prepared as a single, chiral diastereomer via double microwave-assisted aza-Prins cyclization in one-pot or sequential reaction format.     

Enantioselective straightforward access to benzo[b]thiophene analogs of Azatoxin

Horner-Wadsworth Emmons olefination followed by asymmetric hydrogenation allowed the first synthetic access to the chiral thiotryptophan with good enantiomeric excess. Oxazolidinone formation followed by a Pictet–Spengler condensation provided the benzothiophenic analog of Azatoxin.     

An efficient and straightforward access to sulfur substituted [2.2]paracyclophanes: application to stereoselective sulfenate salt alkylation

A straightforward and high-yielding access to various [2.2]paracyclophanes possessing a sulfur-based functional group is reported, the key step being a SEAr reaction mediated by a sulfonium salt. The versatility of the methodology was exemplified by an original application in sulfenate salt chemistry, from which a remarkable chirality transfer was observed.     

Concomitant morpholine ring contraction and pyridine lithiation in 4-morpholinopyridine: straightforward access to N-pyridyl oxazolidines

The reaction of 4-morpholinopyridine with TMSCH₂Li induced an unprecedented anionic ring contraction of the morpholine ring in an exo-trig mode while lithiating the pyridine ring regioselectively at C-3. The one-pot process offers a straightforward route to functional oxazolidinyl pyridines.     

Arylbutyltellurides as precursors of dilithium arylthienylcyanocuprates in a straightforward approach to phenethylamine derivatives

The ring opening reaction of N-tosyl aziridines with dilithium arylthienylcyanocuprates generated from arylbutyltellurides produced phenethylamine derivatives in good to excellent yields.     

Original one-pot microwave-promoted Hunsdiecker-Suzuki strategy: straightforward access to trans-1,2-diarylethenes from cinnamic acids

An original strategy combining a Hunsdiecker-type bromodecarboxylation and a Suzuki cross-coupling reaction starting from various cinnamic acids has been developed in one-pot and under microwave heating to give trans-1,2-diarylethenes in few minutes.     

Diastereoselective reduction of cyclopropenylcarbinol: new access to anti-cyclopropylcarbinol derivatives

[reaction: see text] Cyclopropenylcarbinol derivatives are regio- and diastereoselectively reduced with LiAlH(4) in Et(2)O into trans-cyclopropylcarbinols as a single isomer. The regioselectivity of the hydroalumination reaction on the cyclopropenyl ring has been mapped out by deuterium labeling experiments.