Reaction of β-chlorovinyltrimethylsilane with lithium

Includes bibliographical references.Includes illustrations.The reaction of both cis- and trans-beta-chlorovinyltrimethyl-silane with lithium in ether proceeds readily under high speed stirring. Half of the resulting organolithium compound mixture was treated with chlorotrimethylsilane and the other portion carbonated. The products of silylation were bis-trimethylsllylethylene, bis-trimethylsilylacetylene and higher boiling compounds, two of which are 1,4-bis-trimethylsilylbutadienes. Diazomethane treatment of the acids obtained from the carbonated portion produced methyl 3-trimethylsilylpropenoate and methyl 4-trimethylsilyl-2-butenoate resulting from the stereospecific insertion of methylene by diazomethane. The carbonated portion also contained bis-trimethylsilylethylene and higher boiling compounds from the coupling of starting material and organolithium compounds, Trans-beta- chlorovinyltrimethylsilane gave products of retained configuration whereas its cis isomer gave products of inverted configuration at room temperature. Products of retained configuration were obtained for the latter only when in situ trapping of the organolithium compound by chlorotrimethylsilane was employed or when chlorotrimethylsilane derivatization was carried out at low temperature (-20°C), Lithiation does not proceed below -30°C. Reaction of cis-beta-chlorovinyltri- methylsilane with lithium in pentane led to in situ elimination; bis-trimethylsilylacetylene was obtained from silylation. and only methyl propargylate from carbonation.M.S. (Master of Science