Fluoride ion-catalyzed desilylative-defluorination for synthetic organic chemistry

The Fluoride Anion-Catalyzed Sulfurization of Thioketones with Elemental Sulfur Leading to Sulfur-Rich Heterocycles: First Sulfurization of Thiochalcones

“…In the 1 H-NMR spectrum (see Supplementary Materials part), along with absorptions of aromatic H atoms, a characteristic set of two doublets with 3 J H,H = 3.0 Hz was found at 5.87 and 6.19 ppm, respectively. In addition, 13 C-NMR revealed a signal of a C q atom at 63.7 ppm and two other signals located at 120.7 and 132.9 ppm, respectively, with clearly different intensities, which could be attributed to a CH=C unit. The elemental analysis confirmed the molecular formula C 15 H 12 S 2 expected for a product of monosulfurization of 3a.…”

“…The main component isolated as the most polar fraction showed in the 1 H-NMR spectrum eight signals with approximately the same intensities located at 1.32, 1.35, 1.51, 1.51, 1.69, 1.71, 1.74, and 1.75 ppm. More important information was found in the 13 C-NMR spectrum, which revealed the presence of two isomeric compounds with very similar patterns of absorptions. The most characteristic ones were those found at 248.18 and 248.39 ppm, which were attributed to two C=S groups of the dithiocarboxylate type.…”

“…The less polar fraction formed a yellowish oil, which in the 1 H-NMR spectrum showed the presence of only two broadened singlets located at 1.42 and 1.69 ppm. More information delivered the 13 C-NMR spectrum with two low field absorptions at 243.0 and 216.6 ppm. Whereas the first signal could be attributed to the C=S group incorporated in the four-membered ring of cyclobutane, the second one was identified as the C=O unit of a cyclobutane moiety.…”

“…In spite of the fact that the fluoride anion is well known as a useful reagent acting not only as a unique catalyst for nucleophilic trifluoromethylation reactions [ 12 ], as a desilylating agent [ 13 ], but also as a strong base [ 14 ], its exploration as an activating reagent for elemental sulfur in the sulfur transfer reactions is limited to two reports only, which are known to date [ 15 , 16 ]. In one of them, Petrov and Marshall demonstrated the utility of the fluoride anion as a potent activator of elemental sulfur used for in situ-generation of reactive hexafluorothioacetone S -sulfide, which subsequently was trapped by ethylenic dipolarophiles yielding corresponding bis-trifluoromethylated 1,2-dithioles in high yields [ 15 ].…”

Functionalized fluoroalkyl and alkenyl silanes: Preparations, reactions, and synthetic applications

“…The same electrochemical reaction is applicable for the preparation of 2-chloro-1,2-difluorovinyltrimethylsilane from 1,2-dichloro-1,2-difluoroethene [65]. Fluoride ion-catalyzed desilylative defluorination [66] of bis(trimethylsilyl)tetrafluoroethane 6b is an alternative method for the preparation of 174a where the vinylsilane 174a is subjected to alkylation with aldehydes in situ without isolation [5].…”