Cadmium reagent

The functionalized cadmium compound dialkoxyphosphinyldifluorometh-ylcadmium is readily prepared by direct reaction of bromodifluoromethanephos-phonates with cadmium metal [13 ] (equation 105). This cadmium reagent shows versatile chemical reactivity and reacts with a wide variety of electrophiles, as illustrated m equations 106-109 [139,140,141, 142]... 

The perfluoroallylcadmium reagent can be prepared similarly by direct reaction of perfluoroallyl iodide with cadmium metal [146] (equation 113). Reaction of this cadmium reagent with ally bromide gives F2C=CFCp2CH2CH=CH2 in 78% yield [146]. 

Perfluoroacetylentc copper compounds also can be prepared via metathesis of the corresponding zinc or cadmium reagents with copper(l) bromide. The zinc or cadmium reagents are formed from the corresponding pentachloroperfluo-roalkaneorl lodoperfluoroalkyne [727 747] (equations 168 and 169)... 

Perfluoroarylcopper compounds are usually prepared from the corresponding perfluoroaryllithium, -magnesium, or -cadmium reagents and copper(I) halides [257] (equation 175). 

The synthesis has been achieved by this last method, using an organo-cadmium reagent. 

A practical method for preparation of fluorinated alkenyl copper reagents has been recently developed from cuprous halides metathesis of the corresponding zinc or cadmium reagents [180]. These copper reagents exhibit excellent stability at room temperature and undergo a variety of coupling reactions with methyl, allyl, vinyl, aryl and acid halides [180] (Scheme 63). More recently, preparation of cyclic perfluoroalkenyl copper reagents has been reported by the same route [156-158]. 

Dialkoxyphosphinydifluoromethyl cadmium reagent can be readily prepared via reaction of diethyl bromodifluoromethylphosphonate with acid-washed cadmium powder [270] (Scheme 93). This cadmium reagent exhibits remarkable stability and versatile chemical reactivity. Typical examples are outlined below [271-273] (Scheme 93). 

Trialkylperfluoroalkyltm derivatives can be prepared via metathesis of tnmethyltin trifluoroacetate with bis(perfluoroalkyl)cadmium reagents [4] (equation 3)... 

Bis(trifluoromethyl)cadmium reagent undergoes a related ligand-exchange process [5] (equation 6)... 

Cadiot-Chodkiewicz reaction, for C-C bond formation, 11, 19 Cadmate complex, formation, 2, 465 Cadmium-carbon bond formation, overview, 2, 462 Cadmium reagents... 

Although no trifluoromethyl derivatives of cadmium had ever been isolated, their attempted synthesis was particularly appealing from several viewpoints. First, alkyl cadmium reagents are typically more... 

The published synthesis uses a cadmium reagent but we should rather use copper nowadays.4 Double alkylation of malonate, again adding the benzyl group last, gives 33. Hydrolysis and decarboxylation releases the free acid 34 which is easily converted into its acid chloride and then with Pr2Cd, or perhaps better P CuLi, into the target molecule 28. 

Though the first carbon atoms in LVII and LVIII are asymmetric, only one of the two possible stereoisomers was obtained in each case. It was suggested that the substantial quantities of sirup accompanying the production of these crystalline substances may have contained the other isomer. The authors propose a plausible ionic mechanism for the reaction of organocadmium compounds with tetraacetylglucosyl bromide, leading alternatively to compounds of types IV or LVII. It was reasoned that a carbonium ion was formed at carbon 1 by attack of the cadmium reagent at the bromide function ... 

The perfluorobenzyl organometallic analog, (perfluorobenzyl)cadmium halide (C(,F5CF2CdX), can be prepared in a similar fashion by direct reaction of perfluoro[(bromomethyl)benzene] and acid-washed cadmium powder in dimethylformamide at room temperature. The cadmium reagent is stable at room temperature for several days, but starts to decompose at 50 C. Like (perfluoroallyl)cadmium, (perfiuorobenzyl)cadmium undergoes functionalization reactions with electrophiles such as iodine and allyl bromide. 

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