Reaction with vinyltin compounds

Xenon difluoride (XeF ) is the electrophilic fluorinating reagent whose reactions with vinyltin compounds have been studied most exhaustively. " A series of vinyl fluorides prepared according to this procedure is listed in Table 1. 

Table 1. Synthesis of Vinyl Fluorides by Reaction of Vinyltin Compounds with Xenon Difluoride...

Table 3. Synthesis of Terminal Fluoroalkenes by Reaction of Vinyltin Compounds with F-Teda BF ...

S.8.5.6.2. by Reaction of Vinyltin Compounds with Transition- or Inner Transition-Metal-Carbonyl Complexes. 

In the presence of excess Vi4Pb, vinyl bromide is also formed, proving that the Pb—C bond is cleaved before bromination of the C=C double bond takes place. Hydrochloric acid in the presence of a twofold excess of Vi4Pb cleaves only one vinyl substituent at — 78°C with saturated lead tetraalkyl compounds this reaction takes place only at much higher temperatures. A comparison of the reactivities with vinyltin compounds is interesting bromine and hydrochloric acid cleave from dibutyldivinyltin not more than one vinyl substituent (238, 248). 

Treatment of vinyllin compounds with xenon difluoride in dichloromethane at 25"C results in low yields of the desired vinyl fluorides with the major products being the corresponding alkenes. In addition to the poor yield of the desired compound the reaction times are long (2-3 d). Attempts to increase the reactivity of the vinyltin compounds by the addition of... 

One of the most convenient synthetic routes for the preparation of vinyl fluorides 2 is by treatment of the corresponding vinyltin compounds 1 with electrophilic fluorinating reagents. This procedure is also used for the preparation of aryl fluorides, since it is well-established that fluorination with electrophilic reagents is facilitated by ipso substitution of a suitable, usually weakly bonded, metal function. In the case of aryl fluorides, the reaction is also carried out using elemental fluorine as the fluorinating agent. ... 

Xenon difluoride is a better fluorinaling reagent for vinyltin compounds than cesium fluoroxysulfate (compare entry 1 in Tables 1 and 2). Besides this, cesium fluoroxysulfate (which can be prepared from elemental fluorine and cesium sulfate) is known to be shock sensitive and to undergo detonation upon hcaling. However, cesium fluoroxysulfate is the alternative choiee in the ease of some vinyltin compounds, such as 2- and 3-(trimethylstannyl)indolcs (Table 2, entries 5 7), whose reactions with xenon difluoride are not effective. 

Terminal difluoro- and fluoroalkenes 7 can be prepared in good yields by reaction of the corresponding fiuorovinyltin or vinyltin compounds with 1 -(chloromethyl)-4-fluoro-1,4-diazonia-bicyclo[2.2.2]octane bis(tetrafluoroborate) (Table 3)."... 

Vinyltin compounds can react with metal carbonyls with either loss or retention of vinyl groups. The extent of reaction depends upon the solvent e.g., (CH2=CH)4Sn reacts with Co2(CO)g in THF to give (CH2=CH)Sn[Co(CO)4]3, whereas in pentane it gives (CH2=CH)2Sn[Co(CO)4]2... 

The reaction of active methine compounds, e.g., ethyl methylcyanoacetate and methylmalononitrile, with vinyltins using palladium catalyst gives 3 -hexene derivatives (Eq. 71) [145]. Participation of two molecules of the methyne compound and two vinyl moieties of the vinyltin in this reaction is obvious, though the actual reaction pathway was not clarified. 

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