Imidazole selones

The treatment of vinyl anions with elemental selenium also leads to seleno-carbonyl compounds via eneselenolate anions (Eqs. 4-6). Deprotonation of l,3-selenothio-2-thione with EDA followed by the reaction with elemental selenium proceeds accompanied with the rearrangement of vinylic skeleton to form l,3-dithio-2-selone derivatives (Eq. 4) [38]. The vinyl anions from oxa-zolines and imidazoles were treated with elemental selenium to give the oxazo-line selone and imidazoline selone after the aqueous workup (Eq. 5) [39]. The reaction of vinyl magnesium halides with elemental selenium and allyl bromide gives allyl vinyl selenides that undergo a seleno-Claisen rearrangement to generate y,6-unsaturated selenoaldehydes (Eq. 6) [40]. 

Finally, the Se NMR evidence of l-mesityl-l,3-dihydro-imidazole-2-selone was much more consistent with the selone 43a (5( Se) = 28ppm, Vsec = 231 Hz] than with the selenol tautomer 43b (Scheme 5.34) [83]. The free energy of activation of prototropic tautomerism of ethyl 2H-perimidine-2-carboxylate 44 (Scheme 5.35)... 

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