Trimethylsilyl amines, with

The stoichiometric reaction of iV-benzylidene(trimethylsilyl)amine with [Cp 2Sm(/r-H)]2 yields a Cp2 Sm-imine-amido complex with a four-membered Sm(NSiMe3)(CPh)N=CHPh chelate ring. Heating of this product under H2 gave -symmetric [Cp2 SmCN]6, which contains an unusual chair-like 18-membered (SmCN)6 ring.620... 

Tellurium nitride was first obtained by the reaction of TeBt4 with liquid ammonia more than 100 years ago. The empirical formula TeN was assigned to this yellow, highly insoluble and explosive substance. However, subsequent analytical data indicated the composition is Tc3N4 which, in contrast to 5.6a and 5.6b, would involve tetravalent tellurium. This conclusion is supported by the recent preparation and structural determination of Te6N8(TeCl4)4 from tellurium tetrachloride and tris(trimethylsilyl)amine (Eq. 5.5). The TceNs molecule (5.12), which is a dimer of Tc3N4, forms a rhombic dodecahedron in which the... 

The important reagent Mc3SiNSO is obtained by the reaction of thionyl chloride with tris(trimethylsilyl)amine at 70°C in the presence of AICI3 (Eq. 9.9). " It may also be prepared by the interaction of sulfur dioxide with HN(SiMc3)2. ... 

A carbon-selenium bond can also be formed [106] by Diels-Alder reaction of the transient selenonitroso species 106 generated by phenylsulfinylselenylchlor-ide reacting with amines or trimethylsilylated amines. Selenonitroso compounds 106 were trapped with 2,3-dimethylbutadiene to afford 1,2-selenazine derivatives 107 (Scheme 2.44) in low yield. 1,2- Selenazines are interesting compounds which are quite unstable (2-3 h), except for the one having an... 

A closely related lithium amidinate with a pendant methyl(trimethylsilyl) amine functionality was prepared by the straightforward route outlined in Scheme 178 (55% yield)... 

By reaction of 2-alkyl-4,6-dichloro-l,3,5-trimethylborazines (alkyl = methyl, ethyl, i-propyl) with bis(trimethylsilyl)amine the tetrameric borazine ring systems 4-6 are produced (Fig. 2) they can be purified by several successive vacuum sublimations (yields 4-60%). If the borazines carry n-propyl and tert-butyl groups in the 2-position or if methylbis(trimethylsilyl)amine is used to bridge the borazine molecules, the macrocyclic ring formation is inhibited [17, 18]. 

Alkyl esters are efficiently dealkylated to trimethylsilyl esters with high concentrations of iodotrimethylsilane either in chloroform or sulfolane solutions at 25-80° or without solvent at 100-110°.Hydrolysis of the trimethylsilyl esters serves to release the carboxylic acid. Amines may be recovered from O-methyl, O-ethyl, and O-benzyl carbamates after reaction with iodotrimethylsilane in chloroform or sulfolane at 50—60° and subsequent methanolysis. The conversion of dimethyl, diethyl, and ethylene acetals and ketals to the parent aldehydes and ketones under aprotic conditions has been accomplished with this reagent. The reactions of alcohols (or the corresponding trimethylsilyl ethers) and aldehydes with iodotrimethylsilane give alkyl iodides and a-iodosilyl ethers,respectively. lodomethyl methyl ether is obtained from cleavage of dimethoxymethane with iodotrimethylsilane. 

As yet, a number of experiments have failed to convert ureas 205 such as N-phenylurea or imidazolin-2-one by silylation amination with excess amines R3NHR4 such as benzylamine or morpholine and excess HMDS 2 as well as equivalent amounts of NH4X (for X=C1, I) via the silylated intermediates 206 and 207 in one reaction step at 110-150°C into their corresponding guanidines 208 with formation of NH3 and HMDSO 7 [35] (Scheme 4.13). This failure is possibly due to the steric repulsion of the two neighbouring bulky trimethylsilyl groups in the assumed activated intermediate 207, which prevents the formation of 207 in the equilibrium with 206. Thus the two step Rathke-method, which demands the prior S-alkylation of 2-thioureas followed by amination with liberation of alkyl-mercaptans, will remain one of the standard syntheses of guanidines [21, 35a,b,c]. 

It is supposed that the nickel enolate intermediate 157 reacts with electrophiles rather than with protons. The successful use of trimethylsilyl-sub-stituted amines (Scheme 57) permits a new carbon-carbon bond to be formed between 157 and electrophiles such as benzaldehyde and ethyl acrylate. The adduct 158 is obtained stereoselectively only by mixing nickel tetracarbonyl, the gem-dibromocyclopropane 150, dimethyl (trimethylsilyl) amine, and an electrophile [82]. gem-Functionalization on a cyclopropane ring carbon atom is attained in this four-component coupling reaction. Phenyl trimethyl silylsulfide serves as an excellent nucleophile to yield the thiol ester, which is in sharp contrast to the formation of a complicated product mixture starting from thiols instead of the silylsulfide [81]. (Scheme 58)... 

With dimethyl(trimethylsilyl)amine, the nickel enolate 162 is capable of reacting with benzaldehyde to produce the condensation product 163 (Scheme 60). 

The preparation of optically active analogues of the natural amino acids has proven reasonable using the reaction of tris(trimethylsilyl) phosphite with chiral aldimines prepared from optically active amines.225 The asymmetric induction has been observed to be as high as 80%, a significant competitive process compared to the multistep approaches available.226227 An alternative one-step approach involving asymmetric induction upon addition to an aldimine derived from a chiral N-substituted urea provided a product with less desirable optical purity.228... 

The first reported synthesis of hydroxyurea (24) consists of the condensation of hy-droxylamine with potassium cyanate (Scheme 7.14) [87]. Condensation of hydroxy-lamine with ethyl carbamate also gives pure hydroxyurea in good yield after recrystallization (Scheme 7.14) [88]. Nitrogen-15 labeled hydroxyurea provides a useful tool for studying the NO-producing reactions of hydroxyurea and can be prepared by the condensation of N-15 labeled hydroxylamine with either potassium cyanate or trimethylsilyl isocyanate followed by silyl group removal (Scheme 7.14) [89, 90]. Addition of hydroxylamine to alkyl or aryl isocyanates yields alkyl or aryl N-hydroxyureas (Scheme 7.14) [91, 92]. The condensation of amines with aromatic N-hydroxy carbamates also produces N-substituted N-hydroxyureas (Scheme 7.14) [93]. 

The photooxidation of tertiary methylamines sensitized by electron acceptors such as 9,10-dicyanoanthracene in the presence of lithium perchlorate results in demethylation thus tropinone yields nortropinone257. Photoinduced cyanation of tertiary amines with oxygen, a sensitizer and trimethylsilyl cyanide results in a-cyano nitriles (equation 88)258. 

The a-arylamino nitriles 251, obtained from primary aromatic amines, trimethylsilyl cyanide and acetone in the presence of zinc chloride, react with methyllithium to give A-t-butylarylamines 252287. Af,Af-Bis(trimethylsilyl)amines 253 (R = allyl, benzyl, 3-phenylpropyl etc.) are formed in 50-88% yields by the action of chlorotrimethylsilane on primary amines in the presence of a catalytic amount of titanium(IV) chloride288. 

Tetrafluoroethane-l,2-disulfenyl dichloride (83) reacts readily with At,iV-bis(trimethylsilyl)amines to give A -substituted tetrafluoro-l,3,2-dithiazolidines (84) (Scheme 16) <85CB281l>. The same type of products are obtained by reaction with a combination of trimethylsilyl azide and alkylarenes <89CB1071>. At a low temperature (83) was reported to be cyclized by NHj to 4,4,5,5-tetrafluoro-1,3,2-dithiazolidine <93JPC9625>. 

Compound 26, likewise, undergoes a series of displacement reactions (Scheme 34). Whereas reaction with copper(I) cyanide replaces only one chlorine atom to yield 136, all are displaced by reactions with ammonia and isopropylamine, diethyl(trimethylsilyl)amine, water, and thiols to give, respectively, 137-140. Some additional transformations are also shown. 

Disilathianes, for example (SiH3)2S and [(CH3)3Si] 2S, have been prepared by several routes, namely, the reaction of iodosilane with silver8 and mercuric2 sulfides halosilanes with lithium sulfide,7 [NH4]SH,9 and [Me3NH]SH7 disilaselenane with H2S10 and trisilylphosphine with sulfur.10 Recently, the synthesis of hexamethyldisilathiane, [(CH3)3Si] 2S, was described from the protolysis of l-(trimethylsilyl)imidazole with H2S and from the dehydrohalogen-ation of chlorotrimethylsilane and H2S with a tertiary amine.11 Both of these methods require about 18 hours. 

An additional modification in the above synthetic scheme is possible by introducing the aromatic diamine in the form of its trimethylsilyl derivative [72]. Monotrimethylsilyl-substituted amines are readily prepared from the free amine with hexamethyldisilazane or trimethylsilyl chloride in the presence of a tertiary amine [73, 74] whereas bis(trimethylsilyl)-substituted amines require more aggressive reagents, such as butyllithium in conjunction with trimethylsilyl chloride [75]. As illustrated in Scheme 19, monotrimethylsilyl-substituted amines react with acyl chlorides to form the corresponding amides and liberate trimethylsilyl chloride. Monotrimethylsilyl-substituted amines are reported to display increased reactivity with acyl chlorides [76], This is of great synthetic importance since the increased reactivity allows for reaction with low basicity amines. Bis(trimethylsilyl)-substituted amines, on the other hand, react with acyl chlorides to form the corresponding JV-trimethylsilyl amides, see Scheme 20. The JV-trimethylsilyl amides are much more soluble in common organic solvents. However, they are hydrolytically unstable and readily convert back to the free amides. 

Alkylbis(trimethylsilyl)amines give alkyliminosulfur difluorides, e.g. 28, upon treatment with sulfur tetrafluoride at low temperature.226... 

Verdini and co-workers 71,81 107 were able to silylate the amine with Af,0-bis(trimethylsilyl)-acetamide 108 (BTMSA) and to ring-open Meldrum s acid in a one-pot procedure without isolating the labile Af-silyl derivative. Additional, less frequently employed methods for the synthesis of C2-substituted malonic acids are summarized in a review. 73 ... 

Using an indirect approach, Olah et al.443 were able to diazotize ammonia [Eq. (4.134)], bis(trimethylsilyl)amine, and isocyanic acid with 15NO+BF4, resulting in the formation of 14N15N, which requires the intermediacy of the parent diazonium ion HN2+. 

Liquid bis(pentamethyldisilanyl)amine is considerably associated as compared with bis(trimethylsilyl)amine, as indicated by the respective values of Trouton s constant, 28.1 and 23.5. This is probably due to the increased availability of vacant silicon 3d orbitals at the silicon-silicon bond which might favor an interaction between two molecules (1,188). 

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