Tnmethylsilyl

Homologation ot aldehydes, ketones, acyl chlondes, two carbon homologation via 2-(tnmethylsilyl)thiazole... 

Acid catalyzed cleavage of aromatic methyl or ethyl ethers Quantitative methoxy group determination Also ether cleavage with tnmethylsilyl Iodide ... 

The tnmethylsilyl enol ether of 1 mdanone (3 2 mmol) in 2 mL of methylene chlonde is added to a mixture of xenon difluonde (4 mmol) and a catalytic amount of pyndimum poly (hydrogen fluonde) m 5 mL of methylene chlonde The mixture IS stured at 0 C for 2 h and poured into dilute sodium bicarbonate solution, tlie organic layer is separated and dned After concentration and column chromatogra phy (silica gel, hexanes), 2-fluoro-1 -mdanone (mp, 59 C) is obtamed in 87% yield... 

The presence of a tnalkylsUyl group in a fluonnated organic compound may be useful to direct further transformations of that matenal Yet m some instances it IS the fluonnated substituent that controls the reactions of the tnalkylsdyl group Contrary to predictions, treatment of tert-hnlyX 3-tnfluoromethyl-6-tnmethylsilyl-phenyl carbamate with rert-butyllithium results m metallation of one of the methyl groups attached to silicon rather than that of the aromatic nng [90] (equation 75)... 

The ubhty of trialkylsilyl trifluoromethanesulfonates (trialkylsilyl tri-flates) IS also well-known [93, 94,95] The simplest of these reagents, tnmethylsilyl tnflate, may be prepared in high yield by the treatment of hexamethyldisiloxane with tnfhc anhydnde [96] (equation 77)... 

The tnmethylsilyl compound can be easily desilylated to yield a carbanion intermediate capable of further reactions [66, 67] (equation 35)... 

These thermotropic cellulose derivatives are of course of interest from the viewpoint of their structure and properties and might be considered for such applications as chiroptical filters. However, they are unlikely to be considered for fiber formation and certainly not for regenerated fibers, as essenti dly they are ethers of cellulose and desubstitution woiild be difficult. Pawlowski et al. (I2fi) prepared a series of cellulose derivatives, namely phenylacetoxy, 4-meflioxyphenyl-acetoxy-, and p-tolylacetoxy cellulose and tnmethylsilyl cellulose that... 

A GENERAL [3+2] ANflULATION CIS-4-EX0-IS0PR0PENYL-1,9-DlNETHYL-8-(TRIMETHYLSILYL)BICYCLO[4.3.0]NON-8-EN-2-ONE (4H-Inden-4-one, 1,3a,5,6,7,7a-hexahyd ro-3,3a-dimethyl-6-(1-methyletheny1)-2-(tnmethylsilyl)-, (3act,6a,7aa)-)... 

The present method offers a more efficient and convenient two step route to the parent a,B-unsaturated acylsilane derivative. The first step in the procedure involves the conversion of allyl alcohol to a 11 y 1 tnmethylsilyl ether, followed by metalation6 (in the same flask) with tert-butyllithium at -75°C. Protonation of the resulting mixture of interconverting lithium derivatives (2 and 3) with aqueous ammonium chloride solution furnishes (1-hydroxy-2-propenyl)tnmethylsilane (4), which is smoothly transformed to (1-oxo-2-propenyl)trimethylsilane by Swern oxidation.6 The acylsilane is obtained in 63-68% overall yield from allyl alcohol in this fashion. 

ETHYL 3-C3-(TRIf THYLSILYLOXY)CYCLOHEX-2-ENYL)]PROPIONATE (2-Cyclohexene-l-propanoic acid, 3-[(tnmethylsilyl )o y]-, ethyl ester)... 

Bis(tnmethylsilyl)ammo)chloro((trimethylsilyl)amLno)borane [10078-93-0]... 

HYDROQUINONE,RESORCINOL, AND CATECHOL] (Vol 13) Phenylbis(tnmethylsilyl)stibme [82363-95-9]... 

Ketene acetals prepared from fluorinated esters by tnmethylsilylation undergo Lewis acid-promoted aldol condensations giving satisfactory yields but low diastereoselectivity [27] (equation 22). 

Another useful reagent for the preparation of alkynyl lodomum tnflates is [cyano(trifluoromethylsulfonyloxy)(phenyl)]iodine [737, 138, 139, 140] prepared from iodosobenzene, trimethylsilyl tnflate, and tnmethylsilyl cyanide (equation 71). This reagent reacts with various stannylacetylenes under very mild conditions to form the corresponding alkynyl iodonium salts in high yields [139] (equation 72)... 

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