220423-14-3Relevant academic research and scientific papers
Iodine-Catalyzed Synthesis of Chalcogenophenes by the Reaction of 1,3-Dienyl Bromides and Potassium Selenocyanate/Potassium Sulfide (KSeCN/K2S)
Maity, Pintu,Ranu, Brindaban C.
, p. 4369 - 4378 (2017/12/26)
The methods available for the synthesis of chalcogenophenes, in general, are associated with drawbacks of harsh conditions, use of costly metals, broad applicability, tedious purification process and low yield. To avoid these drawbacks a transition metal-free iodine-catalyzed reaction of aryl-susbstituted 1,3-dienyl bromides with potassium selenocyanate/potassium sulfide (KSeCN/K2S) leading to the corresponding selenophenes and thiophenes has been developed. Iodine is relatively benign, less expensive and readily available. Several diversely substituted selenophenes and thiophenes have been obtained by this procedure in high yields. Using this procedure 2-(4-chlorophenyl)thiophene, a key intermediate for the synthesis of a melanin concentrating hormone receptor ligand involved in the treatment of eating disorders, weight gain, obesity, depression and anxiety has been synthesized. Although the reaction is one-pot essentially it proceeds in two steps involving a selenocyanate/thiolate intermediate leading to the selenophene/thiophene. The simple operation, use of inexpensive reagents and a metal-free process make this procedure more attractive for an easy access to substituted selenophenes and thiophenes. (Figure presented.).
Palladium-catalyzed direct arylation of selenophene
Rampon, Daniel S.,Wessjohann, Ludger A.,Schneider, Paulo H.
, p. 5987 - 5992 (2014/07/21)
An efficient and convenient method was developed for the regioselective formation of 2-aryl- or 2,5-diarylselenophenes via a palladium-catalyzed direct arylation. This protocol is suitable for a wide range of aryl halides containing different functional groups. The 2-arylated substrates can undergo an additional regioselective direct arylation event furnishing symmetrical or unsymmetrical 2,5-diaryl selenophenes in good yield. Competition experiments and the role of the acid additive are in agreement with a concerted metalation deprotonation (CMD) pathway.
