Methoxy trimethylsilane

FIGURE 8. Arrhenius plots for the reaction of 1,1-diarylsilenes 19a (o) and 19e ( ) with methoxy-trimethylsilane in (a) hexane and (b) acetonitrile solution. Reproduced with permission from Reference 57. Copyright 2001 American Chemical Society... 

The activities of the often used hydroxides and siloxanolates decreases in the order Cs > Rb > K > Li (33). At equal molar concentrations, the rates using the hydroxide or siloxanolate of the same metal have been found to be similar (30). Tetramethy1ammonium siloxanolates exhibit activities close to the cesium siloxanolates (33). Tetramethy1ammonium hydroxide, silanolate, and siloxanolate rapidly decompose above 130 C yielding methanol, methoxy trimethylsilane, or methoxysiloxane respectively and trimethyl amine ( 35). In the cases of the first two compounds listed above, the catalyst breakdown products are fugitive at the decomposition temperature. Thus, the usual need for catalyst neutralization and removal following polymerization is eliminated. They are often termed "transient" catalysts (34). 

Scheme 10. Total synthesis of artemisinin by Schmid and Hofheinz. Conditions (i) ClCH20Me, PhN(CH3)2, DCM, rt. (ii) B2H6/THF, H2O2 (iii) PhCHzBr, KH, THF/DMF (iv) HCl, MeOH (v) PCC, DCM, rt. (vi) LDA, (E)-(3-iodo-l-methyl-l-propenyl)-trimethylsilane (vii) lithium methoxy(trimethylsily)methyhde (viii) Li/NH3 (ix) PCC DCM (x) m-CPBA, DCM (xi) -Bu4NF, THF, rt. (xii) O2 (methylene blue, DCM, rt.) (xiii) HCOOH, DCM.

Methyl vinyl ether Ether, methyl vinyl (8) Ethene, methoxy- (9) (107-25-5) Chlorotrimethylsilane Silane, chlorotrimethyl- (8,9) (75-77-4) l-(Methoxyvinyl)trimethylsilane Silane, (1-methoxyethenyl)trimethyl- (10) (79678-01-6)... 

V-Methoxy-/V-methyIhenzyIidenimmonium methylsulfate, 3328 [(1 -Methoxy-2-methyl-1 butenyl)oxy] trimethylsilane, see 1 -Methoxy-2-methyl-1 -(trimethylsilyloxy)-1 -butene, 3207... 

In another application, the totally regioselective direct anodic methoxylation of (45)-pyrimidinone-4-methyl carboxylate obtained from L-2,4-diamino butyric acid followed by diastereoselective substitution of the methoxy group by allyl trimethylsilane can be combined with the follow-up decarboxylative methoxylation of the carboxy function after hydrolysis. A second methoxy group exchange by allyl trimethylsilane yields the C2-sym-metrical (4i ,6i )-4,6-diallyl-pyrimidin-2-one enantiomerically pure [Eq. (50)] [246]. 

Methoxy- V-niethyIbenzylidenimmonium methylsulfate, 3334 [(l-Methoxy-2-methylbutenyl)oxy]trimethylsilane, see l-Methoxy-2-... 

Cannulate [(1-methoxy-2-methyl-1-propenyl)oxy]trimethylsilane (0.15 ml, 0.734 mmol) from a graduated 2 mL Schlenk flask using a transfer needle (or cannula) (using this technique it is possible to add the initiator to an accuracy of 0.05 mL) by applying pressure from the nitrogen supply as shown in Figure 3.2. 

A few other studies of allylations of N-sulfonyl imines by allylic silanes have been published. Shono et al. found that azetidine derivative 22 can be converted to allyl compound 115 [25b] [Eq. (26)]. The functionalized sulfonamides 116 [Eq. (27)] have all been alkylated with allyl trimethylsilane and Lewis acids [34]. In general, the best yields of 117 were obtained with SnCl4, BF3 etherate, Znl2 and FeCl3 as catalysts. Lower yields were obtained with TiCl4 and Et2AlCl. Similarly, the a-hydroxy and a-methoxy sulfonamides 51 could be alkylated to give... 

A useful Mannich-type reaction can be carried out in an fluorous biphasic system, by use of perfluorodecalin (Ci0Fi8, cis- and trans mixture) as the fluorous solvent and hexane as the organic solvent and perfluorinated rare earth metal salts such as Sc(0S02C8F17)3 or Yb(0S02C8Fi7)3 (2.0mol%) as the catalyst. The Mannich-type reaction of arylaldehydes with aromatic amines and (l-methoxy-2-methylpropeny-loxy)trimethylsilane can be carried out many times without reloading the catalyst and the fluorous solvent (Equation 4.27) [48]. 

Homologation of Arenes and Alk-l-enes, Methoxy(phenyl-thio)trimethylsilylmethane undergoes Friedel-Crafts reaction with arenes in the presence of Lewis acids such as titanium(IV) chloride and tin(IV) chloride to afford (aryl(phenylthio)methyl)-trimethylsilanes (eq 12). This reagent also reacts with terminal alkenes in the presence of SnCU to give ene products (eq 13). ... 

Acyl Silanes. Although acyl trimethylsilanes are known, they are usually unstable and lead to poor diastereoselectivity in aldol reactions. TBDMS acyl silanes, however, were prepared in 50% yield from 1-methoxy- 1-lithiopropene in the presence of TMEDA at rt (eq 20). The lithium enolates of TBDMS acyl silanes were treated with aldehydes to give the corresponding aldol products in reasonable yields. 

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