Diselenides and Allyl Selenides as Glutathione Peroxidase Mimetics. Remarkable Activity of Cyclic Seleninates Produced in Situ by the Oxidation of Allyl ω-Hydroxyalkyl Selenides

Abstract

A series of aliphatic diselenides and selenides containing coordinating substituents was tested for glutathione peroxidase (GPx)-like catalytic activity in a model system in which the reduction of tert-butyl hydroperoxide with benzyl thiol to afford dibenzyl disulfide and tert-butyl alcohol was performed under standard conditions and monitored by HPLC. Although the diselenides showed generally poor catalytic activity, allyl selenides proved more effective. In particular, allyl 3-hydroxypropyl selenide (25) rapidly generated 1,2-oxaselenolane Se-oxide (31) in situ by a series of oxidation and [2,3]sigmatropic rearrangement steps. The remarkably active cyclic seleninate 31 proved to be the true catalyst, reacting with the thiol via a postulated mechanism in which the thioseleninate 32 is first produced, followed by further thiolysis to selenenic acid 33 and oxidation-dehydration to regenerate 31. In contrast to catalysis with GPx, formation of the corresponding selenenyl sulfide 34 comprises a competing deactivation pathway in the catalytic cycle of 31, as a separate experiment revealed that authentic 34 was a much less effective catalyst than 31. 1,2-Oxaselenane Se-oxide (37), the six-membered homologue of 31, was formed similarly from allyl 4-hydroxybutyl selenide (26), but proved a less effective catalyst than 31. Compounds 31 and 37 are the first examples of unsubstituted monocyclic seleninate esters.

Construction of a Artificial Glutathione Peroxidase with Temperature‐Dependent Activity Based on a Supramolecular Graft Copolymer

“…[2] Recently, owing to its biologically crucial role, our group [3] and other researchers [4] have devoted considerable efforts to produce organoselenium/tellurium compounds with the properties of GPx. As appropriate amounts of ROS play important roles in controlling stress-related diseases and maintaining normal metabolism, the designing of artificial GPx with adjustable catalytic activity is significant.…”

Giant Nanotubes Loaded with Artificial Peroxidase Centers: Self‐Assembly of Supramolecular Amphiphiles as a Tool To Functionalize Nanotubes

“…[11] To date, many artificial GPx models have been designed by introducing a selenium/tellurium catalytic center into existing or artificially generated substrate-binding scaffolds. [12] b-CD, which has seven glucose units, can recognize the adamantyl moiety well, and this typical host-guest pair has been widely utilized to build up supramolecular materials and devices [8a-e] as it can form stable 1:1 complexes in some polar solvents, such as water and dimethylformamide (DMF).…”

Palladium‐Catalyzed Intramolecular Selenocarbamoylation of Allenes with Carbamoselenoates: A New Entry to α,β‐Unsaturated Lactams

“…[7] For all runs listed in Table 1, no regioisomer of 6, which may arise by the addition to the inner double bond of the allene unit, was detected. As a synthetic transformation of these products, [8][9][10] 6c was converted into allyl alcohol 8 by oxidation with m-CPBA followed by hydrolysis [Equation (4)]. …”