Carbonyl olefination reaction using silyl-substituted organometallic compounds

Abstract

stant was determined as 0.978 k 0.002 for 0.470 and 0.990 M lithium nitrate in liquid ammonia at -33". The constant was calculated from the standard values given by Gmelin.11 The cell was placed in 850 ml of a liquid ammonia suspension of dilithium acetylidelz a t -33" in a 1-1. flask. Acetylene was admitted to the suspension by means of a fritted-glass disperser a t a rate of 146 ml/min. Aliquots of 5 ml each were withdrawn a t 8.8-min intervals by means of a pipet whose only entrance was a medium-fritted-glass filter, 80 that only dissolved material was withdrawn. At the same time, the resistance of the solution was determined. Each aliquot was hydrolyzed a t once in water and the pipet thoroughly washed with water. The solution was boiled until evolution of ammonia ceased, cooled, and titrated with 0.Trimethylsilyl-substituted organometallic compounds, (CH8)8SiCHMR, have been demonstrated to be effective intermediates in the conversion of carbonyl compounds to the corresponding olefins, >C=CHR.These conversions, which involve the formation and decomposition of + SiCHRC(OM)< compounds, appear to be closely related to the classical methods of preparing olefins from reactions of phosphorus-substituted carbanions with aldehydes and ketones.

Definition of green synthetic tools based on safer reaction media, heterogeneous catalysis, and flow technology

“…For this reason, several silylated nuleophiles have been developed and originated a corresponding interesting chemistry [84][85][86][87][88][89][90].…”

peri-Interactions in Naphthalenes, 14 [1]. Pyramidalization versus Planarization at Nitrogen in 8-Dialkylamino-naphth-1-yl Compounds as a Measure of peri Bond Formation

“…Considerable C-H acidity of the conjugate acid would be anticipated due to three Si atoms in α-positions (cf. the Peterson olefination [67]): Oehme's ylidic formula is an adequate representation of the molecule while the silene formula is misleading. The ylidic formula explains the entirely different chemical properties of the stable DAN-Si compounds and the corresponding 8-MeO-C 10 H 6 -Si compounds which are indeed arylsubstituted silenes because of the poor σ -donicity of MeO and hence unstable.…”

Acyl-und Alkylidenarsane, V [1] (Dimethylaminomethyliden)-phenylar8an, ein acyclisches Alkylidenarsan / Acyl-and Alkylidenearsines, V [1] (Dimethylaminomethylidene)-phenylarsine, an Acyclic Alkylidenearsine

“…Wie das entsprechende Phosphan [24] reagiert auch Phenyl-bis(trimethylsilyl)arsan (la) mit Dimethylformamid (4) In Gegenwart von wenig festem Natriumhydroxid reagieren Phenyl-bis(trimethylsilyl)arsan (la) und Dimethylformamid (4) im Überschuß wesentlich rascher (2). Bereits beim Kontakt des Katalysators mit der Lösung bildet sich eine gelborange Zone, und der Ansatz färbt sich innerhalb weniger Minuten gelb; die Farbe ändert sich innerhalb von Stunden nach rot.…”

“…modifizierten Peterson-Olefinierung [2] kann bei den ähnlichen Umsetzungen der Carbonyl-Komponenten mit den entsprechenden Lithium-trimethylsilylphosphiden statt Hexamethyldisiloxan auch Lithium-trimethylsilanolat abgespalten werden [3, s. auch 4]. Die Synthese von Alkylidenarsanen wie etwa die der Arsamethincyanine [5], der Arsabenzole [6] und der Benzazarsole [7] sowie der l-(Trimethylsiloxy)alkyliden- [8] und der Diphenylmethyliden-Derivate [9] oder verwandter Verbindungen [10][11][12][13] zeigt nun, daß die zur Darstellung von Alkylidenphosphanen ausgearbeiteten Verfahren [6,[14][15][16][17][18][19][20][21][22] häufig erfolgreich auf die entsprechenden Arsane übertragen werden können.…”