Triethylammonium reactions with

Stereoselective and chemoselective semihydrogenation of the internal alkyne 208 to the ew-alkene 210 is achieved by the Pd-catalyzed reaction of some hydride sources. Tetramethyldihydrosiloxane (TMDHS) (209) i.s used in the presence of AcOH[116]. (EtO)3SiH in aqueous THF is also effective for the reduction of alkynes to di-alkenes[l 17], Semihydrogenation to the d.v-alkene 211 is possible also with triethylammonium formate with Pd on carbon[118]. Good yields and high cis selectivity are obtained by catalysis with Pd2fdba)3-Bu3P[119],... 

In this context, it is interesting to note that the first synthesis of 2, 3 -0,0-cyclic phosphorothioate 22a was reported by Eckstein in 1968 [25], He also isolated pure Rp diastereomer by fractional crystallization of the triethylammonium salts [26] and used it as reference to determine the absolute configurations of the other phosphorothioate analogues [27], 2, 3 -0,0-Cyclic H-phosphonate 20a was used as a key substrate for the synthesis of uridine 2, 3 -0,0-cyclic boranophosphate 27. Silylation of H-phosphate 20a gave the phosphite triester 25 (two diastereomers). Its boronation, with simultaneous removal of the trimethylsilyl group, was achieved by its reaction with borane-A.A-diisopropylethylamine complex (DIPEA-BH3). 

Sulfenyl fluorides are extremely unstable and therefore only few perhalosulfenyl fluorides have so far been reported122. The formal addition of the elements of methanesulfenyl fluoride to carbon-carbon double bonds has been obtained123 by a one-pot reaction with dimethyl(methylthio)sulfonium tetrafluoroborate and triethylammonium tris(hydrofluo-ride). With this system also the addition to double bonds is highly stereoselective, at least... 

Burgess reagent, (methoxycarbonylsulfamoyl)triethylammonium hydroxide, usually used for the dehydration of secondary or tertiary alcohols, was successfully employed in the formation of cyclic sulfamidates from the corresponding epoxides. It was further shown that the same reaction with aromatic epoxides resulted in the formation of seven-membered ring systems, for example, 57 (Figure 23) <2003SL1247>. 

Aziridinyl ketones can be synthesized from unsaturated carbonyls using a series of other methods. For example, azabicyclo[4.1.0]heptanone 27 was obtained from cyclohexenone 25 in its reaction with TV-bromotoluenesulfona-mide sodium salt 33 [49] (Scheme 1.10). The reaction of chalcone with N-chlorotoluenesulfonamide in the presence of silver nitrite is described in [50]. Trans-Aziridinyl ketone 18 was synthesized by reacting chalcone 22 with N,N-diamino-l,4-diazoniabicyclo[2.2.2.]octane dinitrate 34 and sodium hydride in 2-propanol [30, 51]. Aziridinyl ketones can be obtained in the reaction of a -unsaturated ketones with A,A-dichlorosulfonamines [52] and with amines in the presence of lead tetraacetate and trifluoroacetic acid [53] or in the presence of triethylammonium acetate under electrochemical reaction conditions [54]. 

Acyl selenides. The triethylammonium salt of carboxylic acids reacts with C6H5SeCl and Bu3P in THF to form selenoesters in 62-85% yield. These products on reaction with Bu3SnH (AIBN) furnish acyl radicals. 

Appropriately functionalized alkenes (enamines, a-haloalkenes, silylenoi ethers, acylvinyl phosphonium salts) are frequently employed as the CC fragment in reaction with amidines, guanidines and ureas. An -chloro-A -alkylamidine will react with the enamine derived from an aldehyde to give in the first instance a 2-imidazoline (4). Such compounds deaminate readily to produce the fully aromatic imidazoles (5), especially when heated with pyridinium or triethylammonium chlorides or 50% sulfuric acid (Scheme 4.3.3). 

The syntheses of the 5 -hydrogenphosphonothioate derivatives of AZT, d4T and ddl (189a-i) have been reported. They were prepared through sequential one-pot reactions, i.e. coupling of triethylammonium phosphinate with different alcohols in the presence of pivaloyl chloride, following oxidation with elemental sulfur and further condensation with the nucleoside analogues in the presence of pivaloyl chloride. 

Perfluorinated olefins have been found to give both vinyl azides and the saturated fluoroazides on reaction with triethylammonium azide apparently the intermediate carbanion tends to abstract a proton in this case. Reaction of hexafluoropropene (28) with sodium azide in DMF leads stereospecifically to the trans azide 29. 

Reaction with phosphorus oxychloride 806 Carbon disulfide (18 ml, 0.3 mole) is dropped into a stirred solution of an amine (0.3 mole) and anhydrous triethylamine (126 ml, 0.9 mole) in anhydrous ether (150 ml) at —5° with aromatic amines the mixture is set aside overnight. Then a solution of phosphorus oxychloride (28 ml, 0.3 mole) in anhydrous ether (30 ml) is dropped in, with stirring, at —10° to —5°. Next day the precipitated triethylammonium chloride is filtered off and stirred thoroughly with two portions of ether. The ethereal solutions are extracted with sodium hydrogen carbonate solution and with water, dried over sodium sulfate, concentrated, and fractionated. Yields are about 60%. 

Phase transfer reaction of the conjugate base of the JV,iV,iV -trialkylsulphamides (345) in the presence of benzyl triethylammonium chloride with chloromethyl ethyl ether or chloromethyl alkylthioethers yields the N,iV-dialkyl-iV -alkyl-iV -ether and thioether sulphamides (341)365 (equation 117). 

The first attempt at a nucleophilic substitution reaction in an ionic liquid was carried out by Ford and coworkers [124-126]. Here, the rates of reaction of halide ion (in the form of its triethylammonium salt) with methyl tosylate in the molten salt triethylhexylammonium triethylhexylborate were studied (Scheme 5.2-56). This was compared with similar reactions in dimethyl formamide (DMF) and methanol. The reaction rates in the molten salt appeared to be intermediate in rate between methanol and DMF (a dipolar aprotic solvent known to accelerate Sn2 substitution reactions). 

A report from Stec s laboratory describes the preparation and separation of the diastereoisomers of triethylammonium 5 -0-Tbdms-thymidine 3 -0-meth-anephosphonothioate, and their reaction with p-nitrophenylsulfenyl chloride to... 

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