Zinc-mediated reductive dimerizations of telluroxanthone and selenoxanthone. Tellurium-selenium selectivity
Reductive dimerizations of 9H-selenoxanthen-9-one (3) and 9H-telluroxanthen-9-one (4) (1:1) with zinc in boiling AcOH and HCl for 1 hour gave the bistricyclic ethanes 9,9'-bi(9H-selenoxanthene (10), 9,9'-bi(9H-telluroxanthene) (11) and 9-(9'H-telluroxanthen-9'-yl)-9H-selenoxanthene (12) in the ratios 21 (10):35 (11):44 (12) (in addition to 9H-selenoxanthene (13) and 9H-telluroxanthene (14)) Analogous reactions of 4 and 9H-thioxanthen-9-one (9) (1:1) and 3 and 9 (1:1) gave the corresponding bistricyclic ethanes. The reactions were chalcogen selective with a preference towards the tellurium-bridged bistricyclic ethanes. (C) 2000 Elsevier Science Ltd.
Levy,Agranat
p. 6157 - 6160
(2007/10/03)
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New syntheses of the telluroxanthene and telluroxanthone are presented. Furthermore, new tellurium-containing esters and 2-tellurium-substituted diphenylmethane derivatives have been prepared, which could not be photo- or thermochemically cyclized to dibe
Lohner,Praefcke
p. 167 - 176
(2007/10/02)
Telluraxanthene
Telluraxanthene was obtained by intramolecular electrophilic cyclization of 2-trichlorotelluriodiphenylmethane with subsequent reduction of the intermediately formed 10,10-dichlorotelluraxanthene.The chemical reactions that occur at the tellurium atom and