Stereoselective Synthesis of Alkynyl Vinyl Chalcogenides via Horner-Wittig Reaction

Abstract

New (diphenylphosphoryl)methyl phenylethynyl sulfides, selenides, or tellurides were prepared by the reaction of (diphenylphosphoryl)methyl p-toluenesulfonate with alkynethiols, -selenols, or -tellurols at room temperature. The (diphenylphosphoryl)methyl phenylethynyl sulfides, selenides, or tellurides reacted with aldehydes and cyclic ketones to give the corresponding alkynyl vinyl sulfides, selenides, or tellurides, with preferential E-stereochemistry, in a Horner-Wittig-type reaction.Organochalcogenium compounds have become the key component of a variety of versatile and useful reagents for organic synthesis. The multiple applications of organochalcogenium chemistry have been well described in a number of review articles 1 and books. 2 Functionalized alkynyl 3 and alkenyl 4 chalcogenides have a great potential in organic synthesis, since they are valuable intermediates for the selective preparation of several organic compounds. Furthermore, methods for the synthesis of chalcogeno-substituted acetylenes have also been described in recent years, 3,5 although in a reduced number compared to their vinylic counterparts. The most common approach to alkynyl chalcogenides employs the reaction of a metal alkynide with elemental chalcogenium followed by reaction with an alkyl halide or an appropriate electrophilic reagent. 5aAmong the many applications of vinyl selenides, divinyl selenides, and vinyl sulfides, the cross-coupling reaction with Grignard reagents catalyzed by nickel 6 and palladium 7 to give the corresponding cross-coupled products, has been described. On the other hand, palladium-4a,8 and nickel-catalyzed 6a,9 cross-coupling reactions and tellurium-metal exchange reactions 10 demonstrate the usefulness of vinyl tellurides.Except for alkynyl vinyl sulfides, alkynyl vinyl chalcogenides constitute a nearly unexplored class of unsaturated chalcogenides. 11-13 Their preparation include multistep sequences employing aldehydes or 2-chloroethyl thiocyanate 13 and the reaction of lithium acetylides with b-chlorovinyl sulfenamides. 11 The sulfur derivatives, as the corresponding sulfoxides and sulfones, were converted into sulfur, selenium, or nitrogen heterocycles by reaction with sodium sulfide, sodium selenide, or methylamine. 14 Alkynyl vinyl sulfides were also claimed to have pesticide and bactericide activity. 15In light of the above comments and from our continuous interest in the development of new vinyl chalcogenides based on Horner-Wittig reaction, 16 we became interested in the development of practical stereoselective synthetic methods for alkynyl vinyl chalcogenides. For instance, we have recently described a detailed study of the synthesis of symmetrical and unsymmetrical divinyl sulfides, selenides, and tellurides from chalcogenyl phosphonates and phosphine oxides, by reaction with arylaldehydes and cyclic ketones. 17 Thus, as a continuation of this study, we planned the preparation of alkynyl vinyl sulfides, selenides, and tellurides by a similar route, starting from (diphenylphosphoryl)methyl phenyl...

Reactions of sodium selenide with ethynyl and bromoethynyl ketones: Stereo- and regioselective synthesis of functionalized divinyl selenides and 1,3-diselenetanes

“…Therefore, the signal at d 7.79 ppm was attributed to the proton of the @CH-CO group and a low-field signal at d 8.55 ppm corresponded to the proton of the SeCH group. Usually protons of the SeCH group in vinylic selenides revealed signals at 6.0-6.9 ppm [2,3,22]. A down-field shift of the vinylic proton was obviously due to electron withdrawing effect of the carbonyl group leading to appearance of partly positive charge on the b-carbon atom of the CH@CH-CO group.…”

“…Vinylic selenides are powerful tools in synthetic organic chemistry [1][2][3][4][5]. The data on diselenetanes synthesis are scarce in the literature.…”

Synthesis of Seleno‐Heterocycles via Electrophilic/Radical Cyclization of Alkyne Containing Heteroatoms

“…mediated intramolecular cyclization of (Z)-chalcogenoenyne 244 successfully afforded 2,5-disubstituted-3-(organoseleno)-selenophene 245 (Scheme 80). [139][140] The reaction of butyl[2-(phenylbuta-1,3-diynyl)phenyl]chalcogen 246 with iron(III) chloride hexahydrate and diorganyl diselenide 4 in dichloromethane solvent under reflux condition resulted in the product benzo[b]chalcogenopheno [2,3-d]furan 247 (Scheme 81). [141] The synthesis of selenophene-fused chromene 249 a and 1-(butylselanyl)-selenophene quinolines derivatives 249 b starting from 1,3-diynyl propargyl aryl ethers and propargyl anilines 248 is shown in Scheme 82.…”

The Reaction of Grignard Reagents with Bunte Salts: A Thiol-Free Synthesis of Sulfides

“…The reaction of vinyl Bunte salts gave access to vinyl sulfides (entries 8–12). Notably, this methodology gives a direct route to vinyl alkynyl (entries 8 and 11) and divinyl (entry 12) sulfides which are not readily accessible by other methods. , The use of an alkynyl lithium was also effective (entry 11).…”