Stereoselective synthesis of trans olefins by the reaction of Wittig reagents with selenium. Formation of selenocarbonyl compounds

Selenobenzophenones and Diazoalkanes: Isolation of Tetraarylethylenes by the Reaction of Benzophenone Hydrazones with Diselenium Dibromide

“…The resulting solution was refluxed for 6 h, and the solvents evaporated to give pale‐yellow oily crystals, which were chromatographed over silica gel by elution with hexane and hexane/dichloromethane (1:1) to afford 4,5‐dimethyl‐2,2‐diphenyl‐3,6‐dihydro‐2 H ‐selenopyran ( 8 ) (40 mg, 0.124 mmol). 8: Pale‐yellow oil (ref 26. pale‐yellow oil).…”

Synthesis and Characterization of Symmetrical and Unsymmetrical Analogues of 1,2-bis[bis(4-chlorophenyl) Methyl] Diselane

“…Margolis and Pittman [11] prepared bis(diphenylmethyl) diselenide by using two methodologies one involve the reduction of benzophenone using hydrogen selenide and another by treating diphenyl methyl bromide with sodium hydrogen selenide. Okama et al [12] reported the synthesis of diphenyl methyl diselenide in satisfactory yields by the reduction of seleonocarbonyl intermediate with NaBH 4 . Kamigata et al [13] have shown the formation of methyl diphenylmethyl selenide and benzyl diphenylmethyl selenide in low yields by the reaction of 1,3-bis(alkylseleno)allenes and diphenyl diazomethane in refluxing benzene.…”

Stannic chloride-induced unsymmetrical CSe bond cleavage of bis(N,N-dimethylcarbamoylseleno)methanes: Novel generation of selenoaldehydes

“…The synthetic methodologies for selenoaldehydes 3 are roughly classified to the five categories, i.e., (i) oxygen-selenium exchanging reactions of aldehydes [4][5][6][7][8][9][10][11][12][13], (ii) direct selenation of intermediary carbenes or carbenoids using elemental selenium [14][15][16], (iii) sigmatropic rearrangement of substituted alkenyl selenides [17], (iv) elimination of selenides bearing a suitable leaving group adjacent to the selenium atom [18][19][20][21], and (v) alkylation of stable selenoformate esters [22][23][24][25]. Most methods required multistep processes to prepare the suitable precursors for selenoaldehydes 3, and these problems just prompted us to the new-type generation of selenoaldehydes 3 through fragmentation of easily preparable symmetrical diselenoacetals.…”