Synthesis of novel oil-soluble fluorinated surfactants via Wittig-Horner reaction

In this paper, the synthesis and characterization of novel oil-soluble fluorinated surfactants were reported. Both Wittig and Wittig-Horner reaction were used for constructing the perfluorinated branch-chain structure, and the latter provided a better method through a three-step synthesis route which was easy worked up and low cost. The surface tension of novel products in toluene, n-hexane and nitromethane with concentrations of 0.1?mol/L, 0.05?mol/L, 0.025?mol/L, 0.0125?mol/L, 0.00625?mol/L and 0?mol/L were examined. The surface tension research of these surfactants showed that they can reduce the surface tension of organic reagents dramatically. For example, compound 1e can reduce the surface tension of nitromethane from 36.6?mN/m to 24.2?mN/m in the concentration of 0.1?mol/L, and the surface tension of toluene was reduced from 28.0?mN/m to 22.7?mN/m when the concentration of compound 1a was 0.1?mol/L.     

Synthesis of olefins via a Wittig reaction mediated by triphenylarsine

An arsine-mediated Wittig reaction for the synthesis of olefins is described. After heating triphenylarsine in the presence of an activated alkyl bromide for 30 min, the resulting arsonium salt condensed with aldehydes in as little as 5 min at room temperature, yielding the olefins in high yields. Aromatic, heteroaromatic, and alkyl aldehydes were all suitable substrates for this process.     

A Convenient Method for the Synthesis of Alkenes from Vic-diols via Cyclic Sulfates with Magnesium Iodide

Reaction of cyclic sulfates of vic-diols with magnesium iodide in acetonitrile produced the corresponding olefins in excellent isolated yields at room temperature. Cyclic sulfates of trans-diols gave trans-alkenes exclusively. Cyclic sulfates of cis-diols gave a mixture of cis- and trans- alkenes. However, the cyclic sulfate of cyclic cis-diol afforded the corresponding cis-alkene only.     

Continuous-flow synthesis of nitriles from aldehydes via Schmidt reaction

Using continuous-flow synthesis of nitriles by Schmidt reaction, a variety of aldehydes could be smoothly transformed into the desired nitriles in good to excellent yields. The mild reaction conditions and the flowing reaction system greatly improved the safety and make the reaction easy to scale up.     

A convenient titanium-mediated intermolecular alkyne-carbonate coupling reaction

A direct diastereoselective titanium-mediated intermolecular coupling of internal alkynes with dialkyl carbonates under Kulinkovich-type reaction conditions is presented. The influence of the structures of the coupling partners on the yields and regioselectivities of this transformation is described.     

A convenient synthesis of quinazoline derivatives via cascade imino-Diels-Alder and oxidation reaction

<正>Quinazoline derivatives were synthesized fromα-iminoesters via a cascade imino-Diels-Alder and then oxidation reaction catalyzed with CuBr_2.This method provided a new strategy for preparing quinazoline derivatives which may be useful in the synthesis of heterocyclic intermediates.     

Efficient synthesis of functionalized olefins by Wittig reaction using Amberlite resin as a mild base

A convenient procedure for the synthesis of olefins by the reaction of stabilized, semistabilized, and nonstabilized phosphorous ylides with various aldehydes or ketone using Amberlite resin as a mild base is described. Our developed method offers facile and racemization-free synthesis of α,β-unsaturated amino esters and chiral allylic amine. The developed methodology offers mild reaction conditions, high efficiency, and facile isolation of the final products, a practical alternative to known procedures.     

Tandem synthesis of functionalized hexaalkyl benzoisoquinolinopyrrolonaphthyridine-hexacarboxylate,via isoquinoline based multi-component reaction

An expedient,synthetic method to fused polycyclic derivatives of isoquinoline is described via tandem reaction of isoquinoline,dialkyl acetylenedicarboxylates and dialkyl chloromalonate.     

New Types of Stable Aldehydes: Formylphosphane and Formylphosphane Oxide

The reactivity of the formyl group in α-phosphorus-substituted aldehydes 1 can be tuned by adjusting the coordination number of the phosphorus atom. When X is a lone pair, the formylphosphanes obtained are stable compounds, whereas when X=O a relatively unstable formylphosphane oxide is produced. R=iPr₂N, cHex₂N.     

A convenient approach to δ-amino-β-ketoesters by vinylogous Mannich reaction of masked acetoacetates

SiCl₄ is an efficient and selective catalyst for the vinylogous Mannich reaction of linear and cyclic synthetic equivalents of acetoacetate dianion, leading to δ-amino-β-ketoesters in moderate to high yields and complete γ-selectivity; anti-diastereoselectivity was observed by using a γ-methyl-substituted cyclic silyloxydiene.     

A convenient synthesis of N-vinyl enamides via the lithiation and ring-opening reaction of 2-phenyl-2-oxazolines

A simple and efficient synthesis of N-vinyl enamides via the lithiation and ring-opening reaction of 2-phenyl-2-oxazolines with lithium diisopropylamide at room temperature has been developed. This method is especially suitable for the synthesis of multifunctional enamides. Good yields have been obtained when the reactions were amplified to gram scale.     

The reaction of hypochlorous acid with olefins. A convenient synthesis of allylic chlorides

The reaction of HOCl with more highly substituted olefins in methylene chloride affords allylic chlorides in 60–80% isolated yields. The utility of the reaction is illustrated with the synthesis of Rose oxide and α-monoterpenes.     

Catalyst-free multicomponent Strecker reaction in acetonitrile

The multicomponent Strecker reaction using trimethylsilyl cyanide was accomplished without any type of Lewis acid. The reaction performed in acetonitrile as solvent gave excellent results for any class of aldehydes (aromatic or aliphatic), as well as amines (aromatic or aliphatic). In many cases, α-aminonitrile product was isolated pure after the usual work-up, with quantitative chemical yields. A comparison between different solvents indicated that acetonitrile is the best choice. The rate comparison using different Lewis acids showed that all of them catalyzed the reaction in a similar extent, the difference with the acid Lewis-free being minimal.     

First total synthesis of salinipyrone A using highly stereoselective vinylogous Mukaiyama aldol reaction

A synthetic approach for the total synthesis of salinipyrone A has been developed. Key steps involve the TiCl₄-mediated vinylogous Mukaiyama aldol reaction (VMAR) of chiral ketene silyl N,O-acetal with propionaldyhyde, an aldol condensation, Witting olefination, and a cyclization. The synthesis proceeds in eight steps.     

Base-Promoted Elimination Reactions of Acetaldehyde N-Alkyl-N,N-Dimethylhydrazonium Salts. A Convenient Synthesis of N,N-Dimethylalkylamines

The title reaction was utilized for efficient conversion of S_N2-reactive alkyl halides to the corresponding N,N-dimethylaIkylamines.     

A novel photochemical Wittig reaction for the synthesis of 2-aryl/alkylbenzofurans

The synthesis of 2-aryl/alkylbenzofurans has been achieved in high yields under photochemical conditions from readily accessible and suitably substituted phosphonium bromides by an intramolecular photochemical Wittig reaction onto aryloxycarbonyl groups.     

A convenient and expeditious synthesis of 3-(N-substituted) aminocoumarins via palladium-catalyzed Buchwald-Hartwig coupling reaction

A convenient protocol for the rapid and efficient synthesis of 3-(N-substituted) aminocoumarins is described. The synthetic route developed involves the Pd-catalyzed C-N coupling reaction from readily available 3-bromocoumarin derivatives in the presence of the catalytic system Pd(OAc)₂/Xantphos. Under these conditions, a series of nucleophiles including amides, sulfonamides, carbamates and functionalized amines, have been successfully reacted to afford the coupling products in fair to good yields.     

A green and convenient protocol for the synthesis of novel pyrazolopyranopyrimidines via a one-pot,four-component reaction in water

Novel tricyclic fused pyrazolopyranopyrimidines containing both biologically active pyranopyrazole and pyranopyrimidine templates are synthesized using a one-pot, four-component reaction involving ethyl acetoacetate, hydrazine hydrate, benzaldehydes, and barbituric acid catalyzed by DABCO in water. Pure target compounds are obtained in very good to excellent yields over short reaction times and with a straightforward work-up procedure.     

A new synthesis of flavonoids via Heck reaction

Several naturally occurring flavonoids have been synthesised following a new proposed method based on the use of the Heck reaction. The key step involves the coupling of an aryl vinyl ketone with an aryl iodide. This procedure affords the flavonoid moiety in a single step.     

A novel and practical synthetic route for the total synthesis of lycopene

A novel route for the total synthesis of lycopene 1 is described. The synthesis is based on: (i) a condensation between 4,4-dimethoxy-3-methylbutanal 4 and methylenebisphosphonic acid tetraethyl ester 5, leading to the C6-phosphonate 6, followed by (ii) a modified Wittig-Horner reaction between 6 and 6-methyl-5-hepten-2-one 7 producing dimethoxy-3,5,9-triene 8, and (iii) another modified Wittig-Horner reaction between C15-phosphonate 2 and C10-triene dialdehyde 3 producing all-E-lycopene. The synthetic steps are easily operated and practical for the large-scale production.