Methoxy trimethylsiloxy

Refluxing cis- or trans-hydroxy methoxy tellurium tetrafluoride with an excess of chlorotrimethylsilane for 12 hours and distilling the reaction mixture, quantitatively produced cis- and trans-methoxy trimethylsiloxy tellurium tetrafluoride3. 

Examples of Dienes and Dienophiles. The synthetic value of D-A reactions can be enhanced in various ways. In addition to hydrocarbon dienes, substituted dienes can be used to introduce functional groups into the products. One example that illustrates the versatility of such reagents is l-methoxy-3-trimethylsiloxy-l,3-butadiene... 

Tris(trimethylsiloxy)-methoxy hexatriene undergoes with aliphatic imidazolides in the presence of a Lewis acid a 5C -f 1C cyclocondensation reaction leading t° aromatic products 18]... 

GTP was employed for the synthesis of block copolymers with the first block PDMAEMA and the second PDEAEMA, poly[2-(diisopropylamino)e-thyl methacrylate], PDIPAEMA or poly[2-(N-morpholino)ethyl methacrylate], PM EM A (Scheme 33) [87]. The reactions took place under an inert atmosphere in THF at room temperature with l-methoxy-l-trimethylsiloxy-2-methyl-1-propane, MTS, as the initiator and tetra-n-butyl ammonium bibenzoate, TBABB, as the catalyst. Little or no homopolymer contamination was evidenced by SEC analysis. Copolymers in high yields with controlled molecular weights and narrow molecular weight distributions were obtained in all cases. The micellar properties of these materials were studied in aqueous solutions. 

Aryl(trimethylsiloxy)carbenes. Acylsilanes (153) undergo a photoinduced C —> O silyl shift leading to aryl(trimethylsiloxy)carbenes (154).73,74 The carbenes 154 can be captured by alcohols to form acetals (157) 73 or by pyridine to give transient ylides (Scheme 29).75 LFP of 153 in TFE produced transient absorptions of the carbocations 155 which were characterized by their reactions with nucleophiles.76 The cations 155 are more reactive than ArPhCH+, but only by factors < 10. Comparison of 154 and 155 with Ar(RO)C and Ar(RO)CH+, respectively, would be of interest. Although LFP was applied to generate methoxy(phenyl)carbene and to monitor its reaction with alcohols,77 no attempt was made to detect the analogous carbocation. 

From singlet oxygen reaction with silyl enol ethers When a carbon tetrachloride solution of 1-methoxy-l-trimethylsiloxy-l-alkene in the presence of tetraphenylporphyrin and bubbling oxygen is irradiated with a 400-W Na lamp, a-trimethylsilyl peroxyesters were obtained in good yield (equation 11) . ... 

The reactions of 1-TMS-cyclohexene oxide are similar (112). Treatment78,82 with sulfuric acid/water (in acetone), concentrated hydrobromic acid, sulfuric acid/ methanol, lithium aluminum hydride afford the corresponding compounds 1,2-di-hydroxy- (113)-, l-bromo-2-hydroxy- (114)-, l-methoxy-2-hydroxy- (115)-, 1-hydroxy-2-TMS-cyclohexane (117). Application of base to 115 yields 1-methoxy-l-cyclohexene (116). Pyrolysis of 112 gives a mixture of 1-trimethylsiloxy-l-cyclo-hexene (118) and 3-trimethylsiloxy-1-cyclohexene (ii9)77 (Scheme 13). 

The synthesis of poly(IB-fr-pivalolactone (PVL)) diblock copolymers was also recently accomplished by site-transformation of living cationic polymerization of IB to AROP of PVL, as shown in Scheme 14 [96, 97]. First, PIB with ffl-carboxylate potassium salt was prepared by capping living PIB with DPE followed by quenching with 1-methoxy-1-trimethylsiloxy-propene (MTSP), and hydrolysis of -methoxycarbonyl end groups. The -carboxyl-... 

Intermolecular addition of carbon nucleophiles to the ri2-pyrrolium complexes has shown limited success because of the decreased reactivity of the iminium moiety coupled with the acidity (pKa 18-20) of the ammine ligands on the osmium, the latter of which prohibits the use of robust nucleophiles. Addition of cyanide ion to the l-methyl-2//-pyr-rolium complex 32 occurs to give the 2-cyano-substituted 3-pyrroline complex 75 as one diastereomer (Figure 15). In contrast, the 1-methyl-3//-pyrrolium species 28, which possesses an acidic C-3-proton in an anti orientation, results in a significant (-30%) amount of deprotonation in addition to the 2-pyrroline complex 78 under the same reaction conditions. Uncharacteristically, 78 is isolated as a 3 2 ratio of isomers, presumably via epimerization at C-2.17 Other potential nucleophiles such as the conjugate base of malononitrile, potassium acetoacetate, and the silyl ketene acetal 2-methoxy-l-methyl-2-(trimethylsiloxy)-l-propene either do not react or result in deprotonation under ambient conditions. 

METHOXYPHENYL)-1,2,5,6-TETRAHYDROPYRIDINE, 68, 188 N-(4-Methoxyphenyl)-Z-4-(trimethylsilyl)-3-butenamine, 68,188 a-Methoxy-o-trifluoromethylphenylacetyl chloride, (S)-(+)-, 69, 15 1-Methoxy-3-(trimethylsiloxy)-1,3-butadiene Silane, [(3-methoxy-1-methylene-... 

C. 5 -Methoxycyclohexan- -one- > A -dicarboxylic acid anhydride. To 3.00 g (0.174 mol) of 1-methoxy-3-trimethylsiloxy- 1,3-butadiene at 0°C (ice bath) is added a total of 980 mg (0.01 mol) of freshly sublimed maleic anhydride in portions of 70-80 mg each over a period of 25 min. When the addition is complete, the ice bath is removed and the clear solution is stirred for 15 min at room temperature (Note 7). Three 5-mL portions of a solution of tetrahydrofuran (35 mL) and 0.1 N hydrochloric acid (15 mL) are added and the solution is stirred for 1 min. The remaining acid solution (35 mL) is added all at once and the resulting solution is poured into 100 mL of chloroform and treated with 25 mL of water. The organic layer is separated and the aqueous layer is extracted four times with 100-mL portions of chloroform. The extracts are combined and dried over anhydrous magnesium sulfate. The solvent is then removed under reduced pressure (Note 8) to provide 2.0 g of an oil which solidifies. Pentane (10 mL) is added to the oily solid and small portions... 

The procedure described here is a scale-up of the published method2 for the preparation of 1 -methoxy-3-trimethylsiloxy-1,3-butadiene (2) from readily available reagents. The preparation of this diene has recently been complemented by a report of the preparation of l,3-bis(trimethysiloxy)-l, 3-butadiene,3 and earlier by a reported synthesis of a 1,3-dialkoxy-l, 3-butadiene.4... 

The electron-donating nature of this diene confers high reactivity and orientational specificity in its reaction with unsymmetrical dienophiles.5 This fact, coupled with the readily available conversion to the a,(3-un-saturated ketone from the imparted functionality, makes l-methoxy-3-trimethylsiloxy-1,3-butadiene (2) a potentially very valuable reagent in organic synthesis. The general reaction scheme is illustrated below ... 

B. Preparation of -methoxy-3-trimethylsiloxy-. 3-butadiene. Tri-ethylamine (575 g, 5.7 mol) is stirred mechanically in a three-necked flask (Note 1). To it is added 10.0 g (0.07 mol) of zinc chloride prepared as described above. The mixture is stirred at room temperature under nitrogen for 1 hr. A solution of 250 g (2.50 mol) of 4-methoxy-3-buten-... 

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