Trimethylsilylethynyl ketones

The addition of a base to an acetylenic ester or ketone provides another method of preparation of enaminones594,595. A convenient one-pot synthesis of enaminones from trimethylsilylethynyl ketones and amines was described596. The reaction of activated methylene compounds, such as cycloalkanones, MeCOPh and PhCH2COOMe, with amide acetals gave high yields of enaminones597 (equation 39). 

Trimethylsilylethynyl ketones. The reagent reacts with acid chlorides to give trimethylsilylethynyl ketones, RCOC Si(CH3>3, in 30-65% yield. ... 

TRIFLUOROMETHYL SULFIDES Trifluoromethylthiocopper. a-TRIMETHYLSILYL ACIDS TrimethyMylacetic acid. a-TRIMETHYLSILYL-7-BUTYROLACTONES Trimethylsilylacetic acid. TRIMETHYLSILYLENOL ETHERS Bis(trimethyl ilyl)formamide. Zinc. TRIMETHYLSILYLETHYNYL KETONES Cuprous trimethylsilylacetylide. TROPONES Diiron nonacarbonyL TROPONOIDS Diiron nonacarbonyL... 

T vo kinds of ethynyl aryl ketones were chosen as starting units. One was ethynyl ketone 50 and the other was m-propynoylphenyl trimethylsilylethynyl ketone 51. Cross-trimerization of these units afforded a mixture of four kinds of trimers trimer 53 from 3 mol of 50,2 1-trimer 52,1 2-trimer 54, and trimer 55 from 3 mol of 51. These trimers could be separated by GPC. The trimer 52 was subjected to the second trimerization reaction after deprotection to afford dodecaketone 49 [55 b]. 

Silyl, germanyl and stannyl alk-l-ynyl ketones have been prepared from 2-lithio-2-(trimethylsilylethynyl)-l,3-dioxolane 448. The deprotonation of the dioxane 447 with n-BuLi at — 65 °C afforded the acyl anion 448 which, after reaction with trimethylsilyl, trimethylgermanyl and trimethylstannyl chloride, gave the expected derivatives (Scheme 117)658. Hydrolysis of these products with 0.01 M sulfuric acid at room temperature in aqueous acetone gave the corresponding acyl derivatives 449. On the other hand, the reaction of the intermediate 448 with alkyl halides allows the synthesis of acetylenic ketones659. 

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