Regioselective Synthesis of Novel Functionalized Dihydro-1,4-thiaselenin-2-ylsufanyl Derivatives under Phase Transfer Catalysis

The regioselective one-pot synthesis of novel functionalized 2,3-dihydro-1,4-thiaselenin-2-ylsufanyl derivatives in high yields based on 2-bromomethyl-1,3-thiaselenole and activated alkenes was developed under phase transfer catalysis conditions. The reactions proceed under mild conditions at room temperature in a regioselective manner with the addition of sodium dihydro-1,4-thiaselenin-2-ylthiolate exclusively at the terminal carbon atom of the double bond of vinyl methyl ketone, alkylacrylates, acrylamide, acrylonitrile, divinyl sulfone, and divinyl sulfoxide. The sodium dihydro-1,4-thiaselenin-2-ylthiolate was generated from 2-[amino(imino)methyl]sulfanyl-2,3-dihydro-1,4-thiaselenine hydrobromide. The latter compound was obtained by the reaction of 2-bromomethyl-1,3-thiaselenole with thiourea, which was accompanied by a rearrangement with ring expansion to the six-membered heterocycle. The obtained 2,3-dihydro-1,4-thiaselenin-2-ylsufanyl derivatives are a novel family of compounds with putative biological activity. The addition products of sodium dihydro-1,4-thiaselenin-2-ylthiolate at one double bond of divinyl sulfone and divinyl sulfoxide, containing vinylsulfonyl and vinylsulfinyl groups, are capable of further addition reactions. A possibility to obtain corresponding alcohol derivatives was shown in the reaction with vinyl methyl ketone

Regio- and Stereoselective One-Pot Synthesis of New Heterocyclic Compounds with Two Selenium Atoms Based on 2-Bromomethyl-1,3-thiaselenole Using Phase Transfer Catalysis

To date, not a single representative of 2,3-dihydro-1,4-thiaselenin-2-yl selenides has been described in the literature. The reaction of 2-bromomethyl-1,3-thiaselenole with potassium selenocyanate at low temperature was accompanied by a rearrangement with ring expansion leading to six-membered 2,3-dihydro-1,4-thiaselenin-2-yl selenocyanate, which was used for the generation of sodium dihydro-1,4-thiaselenin-2-yl selenolate. The latter intermediate was involved in situ in the nucleophilic substitution and addition reactions under phase transfer catalysis conditions. The nucleophilic substitution reactions with alkyl halides gave alkyl, allyl and propargyl 2,3-dihydro-1,4-thiaselenin-2-yl selenides in 93–98% yields. The addition reactions of dihydro-1,4-thiaselenin-2-yl selenolate anion to alkyl acrylates, acrylonitrile and alkyl propiolates proceeded in a regio- and stereoselective fashion affording corresponding functionalized 2,3-dihydro-1,4-thiaselenin-2-yl selenides in 93–98% yields. Thus, the regio- and stereoselective one-pot synthesis of a novel family of 2,3-dihydro-1,4-thiaselenin-2-yl selenides has been developed based 2-bromomethyl-1,3-thiaselenole, potassium selenocyanate, alkyl halides and compound with activated double and triple bonds

1-(4-Chlorophenyl)-2-methyl-2-phenyl-5-(thiophen-2-yl)-1,2-dihydro-3<i>H</i>-pyrrol-3-one

1-(4-Chlorophenyl)-2-methyl-2-phenyl-5-(thiophen-2-yl)-1,2-dihydro-3H-pyrrol-3-one, was synthesized for the first time in 75% yield by the base-catalyzed intramolecular cyclization of 4-((4-chlorophenyl)amino)-4-phenyl-1-(thiophen-2-yl)pent-2-yn-1-one. The starting aminoacetylenic ketone was prepared by cross-coupling of available propargylamines with acyl chlorides in the presence of the PdCl2/CuI/Ph3P catalytic system

Pd/Cu-Catalyzed Cross-Coupling of Bis(2-bromovinyl) Selenides with Terminal Acetylenes: Unusual Involvement of Selanyl Function in the Sonogashira Reaction

The Pd/Cu-catalyzed Sonogashira reaction of (E,E)-bis(2-bromovinyl) selenide and (E,E)-bis(1-bromo-1-hexen-2-yl) selenide with terminal alkynes was found to proceed at room temperature involving both bromine atoms and the selanyl function. As a result, new bis-(1,3-enynyl) selenides and enediyne hydrocarbons are formed with a complete retention of the stereoconfiguration of the initial selenides. Due to steric hindrances in the cross-coupling at the selenyl function in the case of (E,E)-bis(1-bromo-1-hexen-2-yl) selenide, the second process is realized to a lesser extent than with unsubstituted (E,E)-bis(2-bromovinyl) selenide