Decenyl iodonium tetrafluoroborates

Given the propensity of (Z)-l-decenyl(phenyl)iodonium tetrafluoroborate for -elimination (cf. equation 164), it is interesting that the Z-perchlorate salts can be isolated. They do, however, readily decompose to alkynes in CDC13129. 

The reactions of ( )-l-deuterio- and ( )-2-deuterio-l-decenyl(phenyl)iodonium tetrafluoroborates with TB AC1 in dichloromethane have also been investigated (equations 207 and 208)146. The deuterium content of the alkyne, or lack thereof, and the effect of the /Pdeuterium atom on the chlorodecene/decyne ratio are consistent with alkyne production primarily via a cis / -elimination process. 

Anion exchange between (E)-1 -decenyl(phenyl)iodonium tetrafluoroborate and TB AC1 occurs instantaneously in CDC13 at room temperature, while addition of the authentic chloride salt to dichloromethane (rt) affords a 45 55 mixture of (Z)-l-chlorodecene and 1-decyne146. Thus, the reactions shown in equations 206-208 are thought to involve the initial formation of vinyliodonium halides which then give rise to the observed products. 

Once again (cf equation 205), the behavior of tetrabutylammonium fluoride (TBAF) is exceptional. Thus, the treatment of (E)-1 -decenyl(phenyl)iodonium tetrafluoroborate with ten equivalents of TBAF in acetonitrile leads exclusively to 1-decyne (equation 212)146. Furthermore, the reactions of the a- and /1-deuterio isotopomers of the decenyliodonium salt with one equivalent of TBAF in dichloromethane are clearly consistent with alkyne formation via the a-elimination-alkylidenecarbene pathway (equations 213 and 214)146. 

The solvolysis in acetic acid (acetolysis) of -styryl(phenyl)iodonium and -1-decenyl(phenyl)iodonium tetrafluoroborates 1 and 2 has resulted in a particular interest from a mechanistic point of view, as both substrates behave in a different manner under the same conditions. 

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