Generation of a Selenoaldehyde, a Selenoketone, and Telluroaldehydes by [3,3] Sigmatropic Rearrangement of Allyl Alkenyl Selenides and Tellurides

Abstract

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SnCl4‐Induced Unsymmetrical Cleavage of Bis(N,N‐diethylcarbamoyltelluro)‐arylmethanes: Generation of Tellurobenzaldehydes

“…Bis( N,N ‐dimethylcarbamoyl) ditelluride ( 1 ) was prepared according to our previous report . DEF (20 mL) was treated with lithium (347 mg, 50.0 mmol) and elemental tellurium (1.29 g, 10.1 mmol) at 110°C for 20 h, and then oxygen gas was bubbled into the reaction mixture at 0°C for 1.5 h. The reaction was quenched with a small amount of water.…”

“…1 (R 1 = CH 3 ) : Yellow needles, melting point (mp) 121.0–122.0°C; MS ( m/z ) 404 (M + ; 0.4%, 130 Te); IR (KBr) 2908, 1657, 1399, 1350, 1248, 1074, 870 cm −1 ; 1 H NMR (CDCl 3 ) δ = 3.08 (6H, s), 3.11 (6H, s); 13 C NMR (CDCl 3 ) δ = 36.2 (q), 40.7 (q), 145.6 (s). Calcd for C 6 H 12 N 2 O 2 Te 2 : C, 18.04; H, 3.03; N, 7.01.…”

“…Recently, a wide variety of studies on thio‐ and selenoaldehydes have been achieved in the light of their structural interests and the potentiality as new reactive intermediates for the organic reactions . However, only limited research works on generation, trapping, or metal complexation of telluroaldehydes B were reported due to the high instability of the target species toward air, light, and heating, as well as the lack of preparative methods of suitable and easily accessible precursors. In the course of our studies on the novel generation of higher‐row chalcogenocarbonyl compounds, we previously reported a convenient preparation of stable ditelluroacetal derivatives A through the reaction of in situ generated tellurocarbamate ions with gem‐dihaloalkanes .…”

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.…”

“…However, to date, conversion of symmetrical diseleno-or ditelluroacetals into the corresponding chalcogenoaldehydes or chalcogenoketones was not studied at all due to the lack of preparative method of such precursors bearing a suitable chalcogenprotecting group on each chalcogen atoms in spite of their potent synthetic convenience. In the course of our studies on the novel generation of highly reactive species related to higher row chalcogenocarbonyl compounds, we previously reported a convenient preparation of stable ditelluroacetal derivatives 2 using the reaction of N,N-dimethyltellurocarbamate ions with gem-dihaloalkanes [17,26]. These results urged us to the preparation of symmetrical diselenoacetals 1 and the further reactions of 1 with a Lewis acid on the basis of the coordinating interaction between the selenocarbamate moiety and a soft Lewis acid [27].…”