Seleno-Claisen rearrangement

A seleno-Claisen rearrangement has been used179 to synthesise mono-, di-, and tri-allylated selenothioic and S-alkyl esters with high regio- and stereo-selectivity. 

A seleno-Claisen rearrangement was utilized to prepare dihydrobenzo[ ]selenophenes <2003SC2161>. Heating selenide 130 in quinoline produced the dihydrobenzo[, ]selenophene 131 after cyclization of the selenophenol Claisen product (Equation 24). 

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]. 

Hence, Claisen rearrangement of / -amino ester 1404 and /i-alkoxy ester 2511 were followed by further transformation. For similar reactions of /i-seleno esters see refs 233 and 512. 

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