Visible Light‐Promoted Selenylation/Cyclization of Enaminones toward the Formation of 3‐Selanyl‐4H‐Chromen‐4‐Ones

Abstract

A simple and efficient visible‐light‐promoted selenylation/cyclization of enaminones have been realized for the practical synthesis of 3‐selanyl‐4H‐chromen‐4‐ones. This reaction is performed in the mild conditions, no transition metal catalyst or photocatalysts and no additional oxidants are required. In addition, the 3‐selanyl‐4H‐chromen‐4‐ones could be easily converted to selanyl‐functionalized pyrimidines by reacting with benzamidine substrates.

Synthesis of Polysubstituted Furans through Electrochemical Selenocyclization of Homopropargylic Alcohols

“…Water used in the reaction was taken from an ELIX 35 water purification system. Diphenyl diselenide ( 2a ) was purchased from Avra Synthesis Private Ltd. Homopropargylic alcohols ( 1a – b , 1e – i , 1k , 1m – p ) , and diaryl diselenides ( 2b - f ) were synthesized following the reported procedures. Unless otherwise mentioned, other reagents were obtained from commercial sources and used without further purification.…”

Recent Advances in Light-Induced Selenylation

“…2-Hydroxyphenyl enaminone 12.5 has been employed for the preparation of 3-selanyl-4 H -chromen-4-one 12.6 (Scheme , path c) . The PhSe • radical photogenerated in the first step of the reaction is oxidized by oxygen to the corresponding phenylselenyl cation (PhSe + ) that prompted added to the C=C bond of 12.5 to generate a selenium ion.…”

Recent advances in the synthesis of 4H-chromen-4-ones (2012 − 2021)

“…275 Diversely substituted o-hydroxyaryl enaminones underwent selenocyanation and cyclization reactions in the presence of potassium selenocyanate and potassium persulfate in 1,2-DCE at room temperature 276 Scheme 36 Scheme 35 and using PIDA as oxidant in aqueous medium, 271 using N-selenocyanatophthalimide as selenocyanating reagent under grinding conditions, 274 or even using triselenodicyanide, generated in situ from the reaction of selenium dioxide and malononitrile, in DMSO at room temperature 277 to afford 3-selenocyanato-4H-chromen-4-ones. Some 3-phenylselenyl-4H-chromen-4-ones are prompted from the reaction of o-hydroxyaryl enaminones with phenylselenyl chloride mediated by silver triflate in dichloromethane 278 and through selenylation/cyclization reactions of o-hydroxyaryl enaminones with diorganyl diselenides promoted by visible-light LED in a 10:1 mixture of DMF:acetic acid at room temperature (Scheme 37) 279 and using a solvent-free protocol mediated by potassium iodate and glycerol at 100 °C, 266 a series of 3-(alkyl/aryl) selenyl-4H-chromen-4-ones were obtained.…”