Reactions of organolithium complexes with elemental selenium: insertion producing [PhC CSeLi center dot TMEDA center dot THF] 1 and cyclisation producing [{PhC}(4)Se] 2 (TMEDA = [Me2NCH2](2))

The reaction of [PhC equivalent to CLi](n), with Se metal (1:1 equivalents) in THF/TMEDA gives the insertion product [PhC equivalent to CSeLi . TMEDA . THF] 1, which is monomeric in the solid state. The reaction of PhC equiva lent to CPh with Li metal, generating dilithium tetraphenylbutadiene in sit u, followed by the addition of elemental Se gives the selenophene [{PhC}(4) Se] 2, as a result of insertion of Se followed by the elimination of Li2Se. The latter provides a clean and direct route to compounds of this type. (C ) 1999 Elsevier Science S.A. All rights reserved.