Synthesis of Alkynylthiopyridinium Salts and Their Use as Thioketene Equivalents

Abstract

As ynthetic method has been developed for the preparation of dihalo(pyridinium)sulfuranes and their transformation into alkynylthiopyridinium salts, startingf rom inexpensive thiopyridones. Ther eactivity of these salts towards different nucleophiles is evaluated. Most thiols and amines are converted into dithioesters and thioamides, re-spectively;w hereas sterically demanding thiols delivered alkynylthioethers. These results, together with preliminary mechanistic studies revealt hat alkynylthiopyridinium salts can be considered synthetic equivalents of unstablet hioketenes.

Design and Applications of Cyclopropenium Chalcogen Dihalides in Catalysis via C(sp3)–H···X Interactions

“…It was also found that the cyclopropenium planar and the Br–Se–Br bond are in orthogonal and T-shape geometry. It is worth-mentioning that stable crystal that contains X–Z–X bonds (Z = Se, S) is very uncommon and there are only a few relevant literature reports . The C–C bond lengths in the cyclopropene ring (1.36, 1.41 Å) are much shorter than a typical C–C single bond in cyclopropane (1.51 Å) and is close to the length of C–C double bond in cyclopropene (1.30 Å) .…”

Polymorphism of bis(1,3-benzothiazol-2-yl) trithiocarbonate

“…This S1Á Á ÁS3 distance of 3.106 (1) Å , which is considerably shorter than the sum of van der Waals radii (3.78 Å ; Alvarez, 2013), indicates possible attractive chalcogenic interactions. Comparable T-shaped geometries around sulfur were observed by our group for dihalosulfuranes (Talavera et al, 2015;Peñ a et al, 2017;Averesch et al, 2019), where the interaction is even more pronounced because of the electronically depleted sulfur atoms.…”

Novel Cationic Sulfur Reagents and their Application in Electrophilic Group-Transfer Reactions

“…Recently the group of ALCARAZO was able to expand the range of reagents by successful synthesis and application of sulfur-based reagents. A variety of these reagents could be established as platform chemicals for electrophilic cyanation, [41,42,53] alkynylation, [41,[54][55][56] thioalkynylation, [57] alkylation and, in addition, as an aldothioketene mimetic reagent (Scheme 13-II). [55] While the majority of the reported chemistry utilizing these reagents is metal-or at least transition metal-free, herein the expansion to transition metal catalyzed reactions is also presented (See Chapter "C-H FUNCTIONALIZATION UTILIZING THIOIMIDAZOLONE-BASED ELECTROPHILIC TRANSFER REAGENTS").…”