Thioethers, often found in pharmaceuticals and natural compounds, typically involve metal cross-coupling reactions, high temperatures, the use of disagreeable thiols for their synthesis. Here we present a straightforward, thiol-free organocatalytic protocol that uses mild conditions to stitch together inexpensive alcohols aryl chlorides, yielding diverse array alkyl thioethers. Central this approach was discovery tetramethylthiourea can serve as simple sulfur source upon intercepting...

The spiro saga goes on! title reaction sequence provides the first enantioselective synthesis of nitrocyclopropyl oxindoles. method easy access to these new, biologically inspired compounds from readily available starting materials (see scheme).

Remote control of the axial chirality N-(2-t-butylphenyl)succinimides was realized via vinylogous Michael addition 3-substituted cyclohexenones to N-(2-t-butylphenyl)maleimides. 9-Amino(9-deoxy)epi-quinine promoted enantioselective desymmetrization, leading atropisomeric succinimides with two adjacent stereocenters.

The first catalytic enantioselective and diastereoselective synthesis of atropisomeric hydrazides was achieved using a sequential catalysis protocol. This strategy is based on one-pot sequence two organocatalytic cycles featuring the enamine amination branched aldehydes followed by nitrogen alkylation under phase-transfer conditions. resulting axially chiral were obtained directly from commercially available reagents in high yields with good stereocontrol. permutation organocatalysts allowed...

The atroposelective desymmetrization of N-arylmaleimides was realized by means a primary amine catalyzed Diels-Alder reaction enones. chiral axis as new element chirality is generated under the remote control catalyst that selectively drives formal through an exclusive stereochemical outcome.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereoselective synthesis of 3-(ethoxycarbonyl)-4-hydroxy-5-(1-hydroxyalkyl)-2-isoxazoline 2-oxides by reaction 2,3-epoxy aldehydes and ethyl nitroacetate on alumina surfaceGoffredo Rosini, Roberta Galarini, Emanuela Marotta, Paolo RighiCite this: J. Org. Chem. 1990, 55, 3, 781–783Publication Date (Print):February 1, 1990Publication History Published online1 May 2002Published inissue 1 February...

A mixture of 9-amino-(9-deoxy)epi-dihydroquinidine and salicylic acid was able to promote the direct reaction various cyclohexanones with dibenzoyl peroxide, thus affording corresponding protected α-hydroxy carbonyl compounds in high yield enantioselectivity. Interestingly same catalytic salt found be active when 1-indanones derivatives were directly employed peroxide furnishing chiral 1-oxo-2,3-dihydro-1H-inden-2-yl benzoates yields Furthermore their treatment NaBH(4) gives easy access...

The first enantioselective Friedel–Crafts alkylation–acetalization-cascade of naphthols with α,β-unsaturated cyclic ketones and 1H-inden-1-ones was realized. 9-Amino(9-deoxy)epi-quinine A the catalyst choice for realization polycyclic structures high enantiocontrol.

ConspectusAsymmetric synthesis using organic catalysts has evolved since it was first realized and defined. Nowadays, can be considered a valid alternative to transition metal catalysis for synthesizing chiral molecules. According the literature, number of asymmetric organocatalytic processes associated with atropisomer rapidly increased over past 10 years because organocatalysis addresses challenges posed by most widespread strategies used preparing axially molecules satisfactory...

A new methodology for the one-pot direct conversion of 2,3-epoxy alcohols into enantiomerically pure 4-hydroxy-4,5-dihydroisoxazole 2-oxides 1 has been found. The reaction works at room temperature and can be run 5−10 g scale. mixture 4,5-cis 4,5-trans isomers obtained separated as such or bis-TDS ethers. preliminary example reductive cleavage to corresponding amino polyol is also reported.

Five distinct crystal forms of rifaximin (α, β, γ, δ and ε) have been identified characterised by X-ray powder diffraction, solid state 13C NMR, HATR-IR spectroscopy. Changes in the structure may produce differences two to three orders magnitude rate intrinsic dissolution, solubility bioavailability rifaximin. Alteration pharmacokinetic parameters is particular interest; Cmax values range from 1.1 1085.31 ng ml−1 AUC0-24 h 10 4795 ml−1. These findings are relevant therapeutic use

The organocatalytic axially enantioselective Knoevenagel condensation between prochiral cyclohexanones and oxindoles is presented. reaction, promoted by a primary amine, proceeded smoothly furnished unprecedented examples of novel cyclohexylidene displaying axial chirality.

trans-Chalcones have been obtained in good yields and selectivities following an environmentally friendly methodology by using montmorillonite KSF as a reusable heterogeneous catalyst.

The desymmetrization of <i>N</i>-(2-<i>tert</i>-butylphenyl)maleimides was realized by means a Michael reaction <i>N</i>-(<i>tert</i>-butoxycarbonyl)-3-phenyloxindoles leading to the corresponding axially chiral succinimides in high yields. use squaramide cinchonidine organocatalyst fundamental achieve simultaneous remote control stereogenic axis and adjacent quaternary tertiary stereocenters.

The Friedel–Crafts-type reaction between properly functionalized inden-1-ones and 2-naphthols generates a hindered single bond which displays unique preference for an antiperiplanar conformational diastereoisomer. steric hindrance the presence of enantioenriched stereogenic center control distribution two diastereomeric conformers at equilibrium increase energy rotation C(sp3)–C(sp2) bond.

The γ-functionalization of oxindoles bearing nonsymmetric 3-alkylidene groups via vinylogous Michael-type addition to nitroolefins was realized. suppression the interconversion between E and Z isomers starting allowed a site-specific diastereoselective enantioselective transformation. Specific experiments us establish rate-determining step reaction advance robust hypothesis for exclusive formation an s-cis enolate as only reactive intermediate.

The novel vinylogous aldol-lactonization cascade of alkylidene oxindole with trifluoromethyl ketones is presented. reaction, catalyzed by a bifunctional tertiary amine, provides an efficient application the reactivity oxindoles for preparation enantioenriched trifluoromethylated α,β-unsaturated δ-lactones.