148915-35-9

Upstream product

• 117110-45-9 3,6-dihydro-4,5-dimethyl-2H-selenine-2-carbonitrile 
• 94-36-0 dibenzoyl peroxide 
• 937-14-4 3-chloro-benzenecarboperoxoic acid 

Relevant academic research and scientific papers

Novel Oxidative Ring Contraction of Dihydroselenopyrans to Selenophenes

Oxidation of 3,6-dihydro-2H-selenopyrans with an electron-withdrawing group at the 2 position proceeded via an unprecedented ring-contraction to afford selenophenes.

Generation of selenabenzenes bearing an electron-withdrawing group at the 2-position

3,6-Dihydro-2H-selenopyrans 2 with an electron-withdrawing group at the 2-position were prepared by the Diels-Alder reaction of butadienes with selenoaldehydes generated in situ from selenocyanates 1 and triethylamine. Oxidation of the dihydroselenopyraus 2 with 1.5 eq of m-chloroperbenzoic acid provided 2H-selenopyraus 9 and 3,6-dihydro-2H-selenopyran-2-yl m-chlorobenzoates 10. The benzoates 10 were smoothly converted into the selenopyrans 9 using polyphosphoric acid trimethylsilyl ester. The selenopyrans 9 were methylated with methyl trifluoromethanesuflonate to give Se-methyl selenopyranium trifluoromethanesulfonates 12. Deprotonation of the selenonium salts 12 with sodium hydride or triethylamine generated the selenabenzene derivatives 13, but they were too unstable to be isolated. Therefore, we confirmed the generation of 13 by 1H- and 13C-NMR spectroscopy at -30°C.