Seleno-selenocarboxylation

Selenocarboxylate salts are not generally available due to the instability of the corresponding seleno-acids. An indiret method to... 

A series of thio- 46 [51,168] and seleno-carboxylato complexes 47 [175] with tmns-configurations have been synthesized from the reaction of NiCl2(R3P)2 with alkali metal or 0-trimethylsilyl selenocarboxylates (Scheme 4). Telluro-carboxylato nickel complexes 48 Ni(RCOTe)2(R3P)2 are too labile to isolate, although their formation has been confirmed by their H, and Te NMR and IR spectral data [175]. The anionic thiocarboxylato nickel complex 49 is... 

Aromatic acylsulfenyl bromides 154 have been synthesized by reacting thio-carboxylic acid phenylmercury [148], diphenyltin [149], silver [149], or 0-tri-methylsilyl derivatives [232] with bromine or AT-bromosuccinimide (NBS) (Scheme 20). In contrast, the selenium isologues are very sensitive toward oxygen and are also thermally labile. In the reaction of the diphenylarsanyl seleno-carboxylates 107 with NBS, only the formation of the 4-methylbenzoylselenenyl bromide 120 (R=4-CH3C6H4 X=Br) has been proved, by converting it into the jS-bromoethyl selenocarboxylates 121 (X=Br) (see Scheme 18) [135]. 

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