Activation of reducing agents. Sodium hydride containing complex reducing agents

Reactivity of nucleophiles toward and the site of nucleophilic attack on bis(alkylthio) selenides

“…RSSe' + PhLi -RS' + PhSeLi (10) Kinetics of Reaction of Cyanide Ion with Bis(alkylthio) Selenides. Treatment of a bis(alkylthio) selenide with excess cyanide ion in a HCN-CN' buffer in 60% dioxane leads to the disappearance of the bis(alkylthio) selenide in a process that is easily followed spectrophotometrically.…”

“…Since one might expect that RSSe', like RSS', should be a much better leaving group than RS", the large difference between the rates of reaction of «-BuS' with la and «-BuSSBu-« in not only understandable but of a magnitude that seems reasonable given the findings of Harpp and co-workers. 10 For eq 4, the activation energy for the reaction when R = t-Bu (15.4 kcal/mol) is about 7 kcal/mol larger than when R = f-Pr (8.6 kcal/mol). The situation is thus quite closely analogous to the behavior of the thiolate-disulfide exchange reaction.…”

“…To the solution in the reaction flask was then added the proper amount of standard sodium hydroxide to give the desired concentration of thiolate ion, and the exchange reaction was then initiated by the addition and thorough mixing of 30 /zL of a concentrated (0.1-0.4 M) stock solution of lc in anhydrous dioxane. Aliquots (2 mL) of the reaction solution were withdrawn at zero time and appropriate times thereafter (total of [10][11][12] aliquot samples per run) and were immediately neutralized by the addition of a small amount (3-30 gL) of 0.1 N aqueous perchloric acid in order to stop any further exchange. (A control experiment had shown that in neutral or weakly acid solution the rate of exchange of r-Bu*SH with lc is negligible.…”

Cobalt-Catalyzed Methoxycarbonylation of Substituted Dichlorobenzenes as an Example of a Facile Radical Anion Nucleophilic Substitution in Chloroarenes

“…Cobalt-catalysed hydroxy- and alkoxycarbonylation of iodo- and bromobenzenes in the system NaH—sodium alcoholate—cobalt acetate (CoCRACO) has been known since 1979 [24,25]. The authors proposed the radical anion mechanism for this reaction.…”

Activation of reducing agents. Sodium hydride-containing complex reducing agents. 16. FeCRACO, a new reagent for the carbonylation of primary, secondary, and tertiary alkyl halides at atmospheric pressure

“…The cooling bath was removed and the reaction mixture stirred for 1 h. After evaporation of ca. 75% of the solvent, the clear, residual oil was chromatographed on 35 g of silica gel with Et^O-hexane (1/2), affording 331 mg (94%) of the mixture of sulfurous esters 7 as a clear colorless oil: NMR (360 MHz) 4.90-4.83 (m, 1 H), 4.54-4.48 (m, 1 H), 3.98-3.89 (m, 1 H), 3.57 (q, J = 4 Hz, 0.6 H), 2.76-2.67 (d, J = 16 Hz, 1.2 ), 2.51 (q, J = 4 Hz, 0.4 ), 2.19-2.08 (m, 1 ), 2.00-1.70 (methylene envelope, 4 ), 1.31-1.22 (m, 1 H); NMR (100 MHz) 5. 04-4.81 (m, 1 H), 4.68-4.46 (m, 1 ), 4.10-3.86 (m, 1 ), 3.60 (q, J = 4 Hz, 0.6 H) , 2.82 (q, 0.4 H), 2.67 (q, 0.4 H), 2.52 (q, J = 4 Hz, 0.4 H), 2.34-1.10 (methylene envelope, 6.2 ), 0.86 (s, 9 ), 0.03 (s, 6 H); IR (CHC13) 2955,1185,1101 cm™1; mass spectrum, m/e 318 (M+, I) , 261 (10), 197 (84), 153 (26), 79 (70), 77 (100), 59 (27), 41 (25).…”