Silyl azides trimethylsilyl azide

Trimethylsilyl (TMS) derivatives in organic synthesis, 22 695-696 as silylating agents, 22 694 Trimethylsilyl azide, as silylating agent, 22 695-696... 

In contrast, the synthetic pathway using trimethylsilyl triflate and trimethylsilyl, azide followed by hydrogenation, de-O-silylation, condensation with thiocarbonyl diimidazole and spontaneous cyclization of an intermediate isothiocyanate, afforded a (3-anomer in good yield (Scheme 32). 

Anhydride 150 and trimethylsilyl azide in dioxane yielded an acyl azide, which by thermolysis, and Curtius degradation spontaneously furnished the isocyanate 151 (72CB3958 74CB3533). Anhydride 152 was formed by silyl ester cleavage on hydrolysis [73MI2 90JCS(P1)375]. 

Alkenylsilanes react with silyl azide and other organic azides to give bissilylenamines and silylaziridines, respectively, via unstable triazoline intermediates.78 Heating trimethylsilyl azide with cyclohexene or vinyltrieth-ylsilane for 10 days affords a modest yield of the respective aziridine,178 but with carefully purified trimethylsilyl azide, even after 2 weeks of reflux, no olefin consumption is indicated.104 Unstable triazoline intermediates are also formed from the reaction of cyanogen azide,808 picryl azide,29 and arylsulfonyl azides808 with unactivated olefinic bonds. 

Stable triazolines are obtained from aryl azides and V-alkyl and N-aryl maleimides (Scheme 81 )307-309a the reaction succeeds with silyl azides310 and is utilized in the synthesis of polymers from bisazides and bismaleimides.311 312 Unlike maleimides, maleic anhydrides do not yield stable triazolines with trimethylsilyl azide the reaction products are oxazinediones (Section IV,A).310,313,314... 

The monoadduct from norbornadiene and the bulky trimethylsilyl azide is less stable than the bisadduct and spontaneously yields a 1-silylated triazole that isomerizes to a 2-silyltriazole (Scheme 139).104... 

Reaction of triisopropylsilyl enol ether with a combination of iodosylbenzene 18 and trimethylsilyl azide at -15 °C gives directly the /J-azido triisopropylsilyl enol ether 38 in a high yield. A mechanism involving the reductive -elimination of a-iodanyl onium ion 37, probably produced by ligand exchange of in situ generated PhI(N3)OTMS with silyl enol ether, was proposed. Addition of azide to the resulting a,/l-unsaturated onium ion explains the formation of 38 [58,59]. 

Chiral silyl ether 210 was prepared and subjected to azidonation with trimethylsilyl azide (TMSN3) and iodoben-zene diacetate [PhI(OAc)2], which served as a substitute of IN3, to give a-azido-dioxasilepine 211 as a colorless oil, in diastereoselective ratio 1 3 (Equation 40) <20050BC816>. 

Diphenylcarbodiimide reacts with trimethylsilyl azide 596 to give a silylated tettazole derivative 597. ... 

Bis(silyl)diazenes (X3Si—N=N—SiX3), which transfer their silyl groups to double bond systems (i), may act as silylating agents. But neither organyl nor silyl azides could have, so far, been converted into silyltriazenes with bis(trimethylsilyl)diazene (X = Me). Either no reaction... 

Unfortunately, attempts to perform this substitution reaction on cyclohexenol and geraniol led to the exclusive formation of the corresponding silyl ethers. It thus would seem that one requirement for effective carbon-carbon bond formation is that allylic alcohols be secondary and have possess y,y-disubstitution. Pearson, however, discovered a method with less restriction on the natiue of the substrate he used allylic acetates with y-mono-substitution or primary alcohols [96]. Not only ketene silyl acetals but also a diverse set of nucleophiles including aUyl silane, indoles, MOM vinyl ether, trimethylsilyl azide, trimethylsilyl cyanide, and propargyl silane participate in the substitution of y-aryl allylic alcohol 90 to give allylated 91 (Sch. 45). Further experimental evidence suggests that these reactions proceed via ionization to allylic carboca-tions—alcohols 90 and 92 both afforded the identical product 93. 

Trimethylpyridine, 61, 62 N-Trimethylsilylamides, 204 Trimethylsilyl azide, 276, 542 Trimethylsilylcarbene, 544 Trimethylsilyl cyanide, 542-543 Trimethylsilyldiazomethane, 543-544 Trimethylsilyldiethylamine, 544-545 Trimethylsilyl enol ethers, 125, 538 N-(Trimethylsilyl)glycine trimethyl silyl... 

Attack on Unsaturated Carbon. Numerous reports of addition of tertiary phosphites, secondary phosphites, and silyl phosphites to activated olefins have appeared. The addition of secondary phosphites to acryloyl chloride in the presence of trimethylsilyl azide provides a route to 2-isocyanato-ethylphosphonates (13). ... 

Furans have occasionally been used as substrates for pyrimidine syntheses which involve acyclic intermediates as in most of the other ring structures used in the construction of the pyrimidine ring . In the furan example shown (Scheme 92), A(-butylisomaleimide was reacted with trimethylsilyl azide, when the A 3-butyluracil (579) was formed after simple removal of the A(l-silyl group <72JOC1738>. 

Trimethylsilyl-l,3-oxazine-2,4(3 0 dione (287) is formed by reacting maleic anhydride with trimethylsilyl azide at 55-60°C. On treatment with ethanol, the A-silyl bond is cleaved to give 1,3-... 

It is possible to synthesize 1,2,3-triazoles from acetylenes and hydrazoic acid, but the instability of hydrazoic acid has limited this application. Sodium azide is silylated readily with trimethylchlorosilane to produce trimethylsilyl azide [4648-54-8], (CH3)3SiN3, which reacts with acetylenes to produce... 

Trimethylsilyl azide is a reactive silylating agent for primary and 121... 

For acceptor-substituted alkynes, it is possible to use trimethylsilyl azide as transfer reagent (cyanogen azide does not react). The reaction (2-90) is not regiospecific, but the silylated triazoles 2.225 can be hydrolyzed and deprotonated to the anion 2.226. The latter reacts regiospecifically with cyanogen bromide to form the triazole-carbonitrile 2.227, which is in equilibrium with the a-diazo-A -cy-ano-imine 2.228 (Regitz et al., 1981 b). 

J-Carbomethoxypropionyl chloride treated during 1 hr. with trimethylsilyl azide in refluxing CCI4, and the product isolated after 1.5 hrs. heating methyl / -iso-cyanatopropionate. Y 84%. F. e., also from carboxylic acid anhydrides, and sterically hindered compds., s. S. S. Washburne and W. R. Peterson, Jr., Synth. Commun. 2, 227 (1972) J. Am. Oil Chemists Soc. 49, 694 (1972) s. a. reactions with silyl azides, H. R. Kridieldorf, Synthesis 1972, 551, 695. 

Earlier, we observed that diazomethane reacts with MA at 20 C to yield a ring-enlarged lactone 27 due to carbene insertion into the OC—O bond of the anhydride. It has been observed that trimethylsilyl azide (TMSA) instead inserts into the bond between the olefinic carbon and carbonyl grouping. No triazoline derivative was reported. Washburne et utilized this reaction to synthesize oxauracils. They treated MA with TMSA to obtain the silyl derivative 41 which could be converted to oxauracil 42 in a 60-80% overall... 

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