91899-32-0Relevant academic research and scientific papers
The Hydroboration of 3-Chloro-1-trimethylsilyl-1-propyne with Dialkylboranes and Its Application to the Syntheses of (E)-3-Trimethylsilyl-2-alkenes and 3-Trimethylsilyl-1-alkenes
Hoshi, Masayuki,Masuda, Yuzuru,Arase, Akira
, p. 685 - 691 (2007/10/02)
The reaction of 3-chloro-1-trimethylsilyl-1-propyne with a stoichiometric amount of dialkylborane proceeds to the monohydroboration stage, giving a mixture of regioisomers, (Z)-dialkyl(3-chloro-1-trimethylsilyl-1-propenyl)borane and (Z)-dialkylborane.The hydroboration mixture is protonolyzed with acetic acid to give (Z)-3-chloro-1-trimethylsilyl-1-propene in quantitative yield.Treatment of the hydroboration mixture with aqueous sodium hydroxide gives a good yield of highly pure (E)-3-trimethylsilyl-2-alkene whose alkyl group migrates from the boron atom.On the other hand, successive treatment of the hydroboration mixture with methyllithium and acetic acid gives a good yield of 3-trimethylsilyl-1-alkene whose alkyl group migrates from the boron atom.The above procedures provide convenient syntheses of (E)-3-trimethylsilyl-2-alkenes and 3-trimethylsilyl-1-alkenes.It is proposed that both products are afforded through the corresponding allylboranes derived from (Z)-dialkyl(3-chloro-1-trimethylsilyl-1-propenyl)borane, respectively.Thus, the former is formed by hydrolysis of alkylhydroxyborane, while the latter is formed by protonolysis of alkylmethylborane.
Regioselective Synthesis of Allyltrimethylsilanes from Allylic Halides and Allylic Sulfonates. Application to the Synthesis of 2,3-Bis(trimethylsilyl)alk-1-enes
Smith, Janice Gorzynski,Drozda, Susan E.,Petraglia, Susan P.,Quinn, Nina R.,Rice, Elizabeth M.,et al.
, p. 4112 - 4120 (2007/10/02)
The preparation of allyltrimethylsilanes by regioselective pathways is described.Treatment of (E)-1-chloro-2-alkenes with a reagent prepared from 1 equiv each of trimethylsilyllithium and copper(I) iodide in hexamethylphosphoramide to presumably form a (trimethylsilyl)copper reagent affords 3-(trimethylsilyl)-1-alkenes in good to excellent yields with a high regioselectivity.Treatment of these same 1-chloro-2-alkenes with (trimethylsilyl)lithium alone without added copper(I) iodide yields only (E)-1-(trimethylsilyl)-2-alkenes.A single allylic halide thus yields two regioisomeric allyltrimethylsilanes by proper choice of reaction conditions.The reaction of a variety of allylic sulfonates with (trimethylsilyl)copper has also been investigated.The mesylates of 2 deg and 3 deg allylic alcohols yield mixtures of isomeric allyltrimethylsilanes in which the 1-(trimethylsilyl)-2-alkenes predominate.With geraniol, the mesylate was prepared in situ and allowed to react with (trimethylsilyl)copper to afford two isomeric allyltrimethylsilanes in which the 3-(trimethylsilyl)-1-alkene predominates.Finally, these reactions have also been used to prepare a variety of 2,3-bis(trimethylsilyl)alk-1-enes, a class of unsaturated organosilanes which has received little attention in the literature.
