Insertion de l'anhydride sulfureux dans la liaison carbone—cuivre

Alkylcopper reagents add sulfur dioxide at ?40°C and high yields of sulfinic are obtained. Copper sulfinates are easily oxidized by bromine to the corresponding sulfonyl bromides.     

A spectrometric study of a 40-MHz inductively coupled plasma—IV. Assessment of this source in oscillator strength measurements of Ta I and Ta II

An inductively coupled argon plasma was evaluated as a source for the determination of oscillator strength values of several lines of Ta I and Ta II. Although there is a departure from LTE, a partial LTE between excited states of injected elements was assumed. This allowed the authors to consider an excitation temperature of 4800 K in the determination of ?-values of tantalum.     

Vinyl-copper derivatives—XI: Reactivity of Z-alkenyl cuprates towards various electrophiles. Application to the synthesis of some natural products

Z-Alkenylcuprates 1 and 2, prepared in situ by addition of acetylene to alkylcuprates, react with a variety of electrophiles (epoxides, carbon dioxide, aldehydes) and give conjugate addition products with α,β-unsaturated aldehydes, ketones and esters, and with activated cyclopropanes. They also add across the triple bond of some alkynes. The synthesis of natural products (7,9,22) is described.     

Preparation d'acides β-amino-ethyl-phosphoniques

We describe a new, practical, synthesis of β-amino ethyl phosphonic acids. Organolithium reagents generated from nitriles are condensed with bis(dimethyl amino) chlorophosphates, followed by alkylation using phase transfer catalysis, reduction of nitrile group, and acid hydrolysis.     

Stéréochimie de la substitution d'un éther allylique par un organomagnésien en présence de sel cuivreux

The nucleophilic substitution of allyl ethers by an organomagnesium reagent in the presence of a catalytic amount of copper(I) salt occurs by antarafacial attack, either with or without allylic rearrangement. It can be compared to the substitution of allyl esters by lithium organocuprates. The leaving group must be quasi orthogonal to the plane of the double bond. A mechanism is postulated.     

Reactivity of RCu,BF3 and R2CuLi,BF3 towards the ether linkage. Epoxides,acetals and orthoformates

The association of BF₃ to organocopper and cuprate reagents increases dramatically their reactivity towards epoxides. The same reagents cleave acetals to afford the product of substitution of one alkoxy group, whereas orthoformates lead to acetals under conditions where no further attack occurs.     

Vinyl-copper derivatives XII : Stereospecific synthesis of allylic amines by aminomethylation of organocopper reagents

the carbocupration or hydroalumination of alkynes followed by amino-methylation yields allylic amines. The stereochemical integrity of the alkenyl moiety is completely retained in both cases.