Regio- and Stereoselective Synthesis of a Novel Family of Unsaturated Compounds with the S–Se Bond and Their Cyclization to 2,3-Dihydro-1,4-thiaselenines

Abstract

Regio- and stereoselective ring-opening reaction of 2-bromomethyl-1,3-thiaselenole with thiols proceeded as nucleophilic attack at the selenium atom of seleniranium intermediate affording unsaturated selanyl sulfides, (Z)-CH2=CHSCH=CHSeSR, in up to 93% yield. Dithiols were involved in this reaction giving symmetrical polyunsaturated compounds with two S–Se bonds in 70–75% yields. Efficient synthesis of 2-(organylsulfanyl)-2,3-dihydro-1,4-thiaselenines in 69–96% yields was developed by the acid-catalyzed cyclization of the unsaturated selanyl sulfides. Mild reaction conditions (room temperature) and short reaction times are important features of this methodology.

Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

“…This was the result of coupling with the nonequivalent protons of the CH 2 Se group. Similar spectral characteristics were observed for other sixmembered 2,3-dihydro-1,4-thiaselenin-2-yl derivatives [31,32,38,40].…”

“…A fundamental approach to the regio-and stereoselective synthesis of unsaturated functionalized organoselenium compounds was developed during the last ten years based on new directions for nucleophilic substitution reactions proceeding via intermediate seleniranium cations 2 generated from thiaselenole 1. We have carried out new regioselective reactions of thiaselenole 1 with dithiocarbamates [31], ketones [37], thiols [38,39], dithiols [38], and mercapto benzazoles [40]. These are the first examples of a nucleophilic attack at the selenium atom of the seleniranium cation 2 with the generation of a new Se-S bond, yielding new families of linear unsaturated (Z)-2-[(organylsulfanyl)selanyl]ethenyl vinyl sulfides (Scheme 3).…”

Quantum Chemical and Experimental Studies of an Unprecedented Reaction Pathway of Nucleophilic Substitution of 2-Bromomethyl-1,3-thiaselenole with 1,3-Benzothiazole-2-thiol Proceeding Stepwise at Three Different Centers of Seleniranium Intermediates

“…The present work is a necessary continuation of pioneering studies of the new methodology of nucleophilic substitution at three different centers of seleniranium intermediates in reactions of 2-bromomethyl-1,3-thiaselenole (1) with nucleophilic reagents (Scheme 1) [57][58][59][60][61]. The analysis of the data includes a comparison with the previously obtained results on the reactions of 2-bromomethyl-1,3-thiaselenole with sulfur-centered nucleophiles [57][58][59][60].…”

“…2-Bromomethyl-1,3-thiaselenole (1) in solutions exists in equilibrium with intermediate seleniranium cation, which determines its unusual chemical properties [57][58][59][60][61] (Scheme 1). The formation of intermediate seleniranium cation in nucleophilic substitution reactions of thiaselenole 1 with dithiocarbamates was supported by quantum chemical calculations [59].…”

Natural Compounds and Their Structural Analogs in Regio- and Stereoselective Synthesis of New Families of Water-Soluble 2H,3H-[1,3]thia- and -Selenazolo[3,2-a]pyridin-4-ium Heterocycles by Annulation Reactions

“…The selenium-containing heterocyclic drug ebselen is applied for the prevention and treatment of human ischemic stroke [21]. The development of effective approaches to novel selenium heterocycles by regioselective cyclization and annulation reactions is one of the main directions of our research [22][23][24][25][26][27][28][29][30][31]. The reactions of 2-pyridinesulfenyl and 2-pyridineselenenyl chlorides with some alkenes have been described [32][33][34][35][36][37][38][39][40][41].…”