Ultrasound-Promoted One-Pot Synthesis of Mono- or Bis-Substituted Organylselanyl Pyrroles

Abstract

A simple method for the direct mono- and bis-organylselenylation of N-substituted pyrroles through a multicomponent reaction promoted by ultrasonic radiation was described. These sonochemical promoted reactions were performed between different primary amines, 2,5-hexanedione and dialkyl, diheteroaryl, or diaryl diselenides, using catalytic amounts of copper iodide. Depending on the amount of copper iodide and diorganyl diselenide used in the reactions, mono- or bis-organylselenylation products were efficiently synthesized in high yields.

“Green Is the Color”: An Update on Ecofriendly Aspects of Organoselenium Chemistry

“…The reactions were conducted smoothly for 1.5 h in the presence of CuCl (15 mol%) to afford the desired products 26 in moderate to very good yields (Scheme 9). Alves, Perin and co-workers also explored the synergism between Cu(I) species and ultrasound irradiation in the catalytic selenylation of heteroaromatic systems, reporting, in 2019, a simple and efficient multicomponent protocol for the selective synthesis of N-substituted mono-and bis-selenylpyrroles 29 and 30, by reacting primary amines 27, 2,5hexanediones 28 and diorganyl diselenides 6 [36]. Under the optimized reaction conditions the desired products were obtained in poor to excellent yields.…”

Insights into the Recent Synthetic Advances of Organoselenium Compounds

“…[115] Ultrasonic radiation found its application in the synthesis of biologically important mono-and bis-organylselenylated Nsubstituted pyrroles 54 & 55. [116] Therein, the authors have performed multicomponent reaction between 2,5-hexanedione 53, primary amines 52 and diorganyl diselenides with catalytic amount of copper iodide in DMSO to promote the synthesis of pyrrole scaffold along with its selenylation in one-pot reaction vessel (Scheme 23). The synthesis includes Paal-Knorr condensation and direct selenylation CÀ H bond at the 3 rd and 4 th position of pyrroles.…”

Oxyselenocyclization of 2‐Allylphenols for the Synthesis of 2,3‐Dihydrobenzofuran Selenides

“…In these reactions, the electrophiles RSeCl and RSeBr can be obtained from the reaction of diselenides with SO 2 Cl 2 (or Cl 2 ) and Br 2 respectively, or are commercially available [63–65] . Alternatively, the electrophile can be prepared in situ by the oxidative cleavage of the Se–Se bond of diorganyl diselenides using stoichiometric or over‐stoichiometric amounts of several reagents, such as KBr/ m ‐CPBA, [66] [PhI(OAc) 2 ], [67,68] I 2 /DMSO, [69–70] (NH 4 ) 2 S 2 O 8 , [71,72] Oxone®, [73–76] 2,3‐dichloro‐5,6‐dicyanobenzoquinone (DDQ), [77] ceric ammonium nitrate (CAN), [78] SelectFluor®, [79,80] and transition metal (TM)‐based reagents [81–84] …”

“…[63][64][65] Alternatively, the electrophile can be prepared in situ by the oxidative cleavage of the Se-Se bond of diorganyl diselenides using stoichiometric or over-stoichiometric amounts of several reagents, such as KBr/ m-CPBA, [66] [PhI(OAc) 2 ], [67,68] I 2 /DMSO, [69][70] (NH 4 ) 2 S 2 O 8 , [71,72] Oxone®, [73][74][75][76] 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ), [77] ceric ammonium nitrate (CAN), [78] SelectFluor®, [79,80] and transition metal (TM)-based reagents. [81][82][83][84] Therefore, the presence of an organoselenium moiety within the structure of 2,3-dihydrobenzofurans may result in very promising compounds which can potentially found applications on chemical processes and as leading substances for biological assays. Synthetic procedures towards the synthesis of 2-[(organoselanyl)methyl]-2,3-dihydrobenzofurans have already been reported.…”