AbstractDie Carbonylverbindungen (I) reagieren mit in situ erzeugtem CH2LiBr (aus CH2Br2 (II) und Li, LiHg oder n‐Butyl‐Li in der Kälte) in THF zu den Oxiranen (III) (Ausbeuten 35‐52%).

The reaction between bromolithiummethane and carbonyl compounds has been studied. The organometallic species has been generated in situ by reacting dibromomethane and butyllithium, lithium suspension or amalgam in THF. Aliphatic, alicyclic and aromatic aldehydes and ketones give rise to the corresponding epoxides generally in satisfactory yields, α,β-unsaturated carbonyl compounds do not react under the mentioned conditions and this is useful if selectivity is required. The influence of the solvent on the reaction course is also discussed.

The reaction of 1,1-dihalo-alkanes with magnesium and magnesium amalgam has been studied. Methylene bromide and iodide yield, under suitable conditions, a stable solution of methylene magnesium halide which easily olefinates aldehydes and ketones affording the corresponding methylenic olefins in good yields. Other alkylidene halides, under the conditions studied, do not give any stable geminal dimagnesium compound although geminal species are probably present during the in situ reaction between alkylidene halides, carbonyl compounds and magnesium amalgam. A general carbonyl olefination scheme taking into account the majority of the known reactions of this kind is proposed.

Olefins may be obtained by treating epoxides in tetrahydrofuran solution with magnesium amalgam and magnesium bromide.

AbstractDie Reaktion der Dihalogenide (I) mit Mg oder Mg/Hg in Äther führt zu den stabilen Mg‐halogeniden (II), die mit Aldehyden und Ketonen, z.B. (III), die Olefine (IV) (Ausbeuten 40‐70%) bilden.

The reaction of 1,1-dihalo-alkanes with magnesium and magnesium amalgam has been studied. Methylene bromide and iodide yield, under suitable conditions, a stable solution of methylene magnesium halide which easily olefinates aldehydes and ketones affording the corresponding methylenic olefins in good yields. Other alkylidene halides, under the conditions studied, do not give any stable geminal dimagnesium compound although geminal species are probably present during the in situ reaction between alkylidene halides, carbonyl compounds and magnesium amalgam. A general carbonyl olefination scheme taking into account the majority of the known reactions of this kind is proposed.

Chemischer Informationsdienst. Organische ChemieVolume 1, Issue 17 Preparative Organic Chemistry ChemInform Abstract: ALKENE AUS EPOXIDEN DURCH REDUKTIVE ELIMINIERUNG MIT MAGNESIUMBROMID UND MAGNESIUMAMALGAM F. BERTINI, F. BERTINISearch for more papers by this authorP. GRASSELLI, P. GRASSELLISearch for more papers by this authorG. ZUBIANI, G. ZUBIANISearch for more papers by this authorG. CAINELLI, G. CAINELLISearch for more papers by this author F. BERTINI, F. BERTINISearch for more papers by this authorP. GRASSELLI, P. GRASSELLISearch for more papers by this authorG. ZUBIANI, G. ZUBIANISearch for more papers by this authorG. CAINELLI, G. CAINELLISearch for more papers by this author First published: April 28, 1970 https://doi.org/10.1002/chin.197017171Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume1, Issue17April 28, 1970 RelatedInformation

Oxirans may be obtained by treating carbonyl compounds in tetrahydrofuran with methylene bromide and lithium or lithium amalgam.

The straightforward synthesis of polycarbosilanes (PCS) was achieved via the polycondensation of chlorosilanes and chloromethanes using magnesium (Mg) and titanium(IV) tetrachloride (TiCl4). In this polycondensation, TiCl4 acts as an efficient catalyst and the combined use of Mg and TiCl4 is necessary to produce PCS. The resulting PCS are viscous colored oils that are soluble in organic solvents. The number-average molar mass (Mn; 1.0–1.5 kg mol−1) and molar-mass dispersity (ÐM; 1.3–1.9) values of the resulting PCS were determined by size-exclusion chromatography (SEC) using polystyrene standards. The 1H, 13C{1H}, and 29Si{1H} NMR as well as IR spectra of the resulting PCS revealed that they consist of Si–C, Si–H, Si(H)–H, C–C, and Si–Si bonds. The structures of the resulting PCS vary depending on the structures of the monomers and their initial molar ratios. The ceramic yields from the obtained PCS (23–70%) depend on the original structures of the PCS. A plausible mechanism of this polycondensation is proposed based on the results of polycondensations and model reactions.