The oxidation of (Z)-1,2-bis(arylseleno)-1-alkenes is known to afford alkynyl selenoxides via a unique selenoxide anti-elimination mechanism; however, to date, there have been no mechanistic studies of this reaction. During our studies of this transformation, monoselenoxides 6 and 7 were unexpectedly isolated as stable reaction intermediates. In addition, (77)Se NMR studies of the reaction mixture revealed the presence of an intramolecular Se···O interaction and the formation of alkynyl selenoxides. Meanwhile, even at higher temperatures, the reaction of a (Z)-1,2-bis(arylsulfinyl)-1-alkene, the sulfur analog of (Z)-1,2-bis(arylseleninyl)-1-alkenes, did not proceed via sulfoxide elimination but proceeded via isomerization and disproportionation. Therefore, the intramolecular Se···O interaction can be concluded to play a pivotal role in the anti-elimination reaction.

A highly regio-and stereoselective selenoxide elimination of 1,2-bis [4-(trimethylsilyl)phenylseleno]alkanes to give (E)-alkenyl selenoxides and its mechanistic studyThe elimination of a 2-substituted selenoxide is known to provide a variety of different products, which are largely dependent on the nature of the substrate and its substituents. Oxidation of (Z)-1,2-bisarylseleno-1-alkenes lead to formation of bisselenoxide intermediate, which gives the corresponding alkynyl selenide by anti-elimination and subsequent reduction by the ArSeOH byproduct. In this study, the selective elimination of selenoxide from 1,2-bis[4-(trimethylsilyl)phenylseleno]alkanes resulted in the exclusive formation of (E)-alkenyl selenoxides via a 1,2-bisselenoxide intermediate. The oxidation of 1,2-bis[4-(trimethylsilyl)phenylseleno]alkanes with one equivalent of metachloroperoxybenzoic acid resulted in the non-selective formation of several arylseleno alkene derivatives, and it was subsequently shown that the elimination of the corresponding 1,2bisselenoxide proceeds with high regio-and stereoselectivity. Mechanistic investigations for this unique elimination have been performed with 77 Se NMR experiments and computational studies.the corresponding allylic product. [3][4][5] The failure of this strategy for the synthesis of enol derivatives from 2-oxygen-substituted selenides has already been reported. This phenomenon was at- [a] A.

Oxidation of organo‐selenium compounds (I) with MCPBA generates bisselenoxide intermediates which undergo elimination to give products (II) with high regio‐ and E/Z‐selectivity.