One-Pot Synthesis of Aryl Selenonic Acids and Some Unexpected Byproducts

Abstract

The synthesis of aryl selenonic acids was achieved from diverse aryl bromides via a one-pot method involving metalation, selenation, and oxidation with hydrogen peroxide followed by ion exchange to afford the pure products in 77−90% yield. An o-hydroxymethyl derivative was found to dehydrate readily, affording the first example of a cyclic selenonic ester, while two minor byproducts were isolated and shown by X-ray crystallography to be mixed salts of aryl selenonic acids with either the corresponding aryl seleninic or selenious acid.

Chemistry Related to the Catalytic Cycle of the Antioxidant Ebselen

“…This correlates closely with the downfield signal at 1162.5 ppm in the precipitate. In our previous work [93], all of the selenonic acids studied produced 77 Se NMR signals in the 1020-1031 ppm range in D 2 O, consistent with the more upfield signal at 1020.2 ppm. These results suggest that the species present are the free seleninic and selenonic acids 3 and 14, respectively, and not the expected salt 16.…”

“…The selenonic acid derivative of selenocysteine has also been prepared and its x-ray crystal structure was determined [92]. More recently, we described an effective one-pot synthesis of various selenonic acids from aryl bromides [93]. On the other hand, the formation of the isomeric peroxyseleninic acid 15 from 3 does Scheme 3.…”

“…The selenonic acid derivative of selenocysteine has also been prepared and its x-ray crystal structure was determined [92]. More recently, we described an effective one-pot synthesis of various selenonic acids from aryl bromides [93]. On the other hand, the formation of the isomeric peroxyseleninic acid 15 from 3 does not appear to have been reported during the oxidation of ebselen (Mugesh et al [46] also postulated the formation of the corresponding peroxyselenenic acid intermediate (ArSe-OOH) from seleninic acid 3.…”

One-Pot Multicomponent Polymerization, Metal-, and Non-Metal-Catalyzed Synthesis of Organoselenium Compounds

“…In 2021, Sands et al reported the one-pot synthesis of structurally diverse selenonic acids in good yields (up to 90%) from elemental Se and aryl bromides. The reaction involves metalation using t -Butyllithium, selenation, and oxidation using H 2 O 2, followed by ion exchange using Rexyn 101( H ) ion-exchange resin ( Scheme 32 ) [ 81 ].…”

Directing Group Strategy for the Isolation of Organoselenium(VI) Benzoselenonates: Metal-Free Catalysts for Hydrogen Evolution Reaction

“…Here, the quinoline ligand not only facilitated the installation of Se in the benzamide ring but also avoided the use of 1,10-phenanthroline ligand in catalysis as itself serves as a ligand and also helps in stabilizing high oxidation VI state of selenium. In comparison to divalent and tetravalent, hexavalent organoseleniums are underexplored and mainly used as peroxide-decomposing/activating mimetics. , …”