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چکیده
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Transition metal-catalyzed asymmetric 1,4-addition of terminal alkynes to β-substituted α,β-unsaturated compounds is one of the most efficient methods to construct a stereocenter at the propargylic position. Recently, we reported that cobalt complexes can catalyze the 1,6-addition of (triisopropylsilyl)-acetylene to α,β,γ,δ-unsaturated carbonyl compounds. In this kind of reactions there are some difficulty which induction the polarity can control the regioselectivity as well as the enantioselectivity. In this work we omit the effect of polarity by using non-polar cyclo-1,3-dienes compounds. Asymmetric addition of (t-buthyldiphenylsilyl)-acetylene to cyclo-1,3-dienes compounds took place in the presence of a cobalt/ chiraphos catalyst to give the δ-alkynylated cycloalkene in high yields with high regio-and enantioselectivity. Transformation of products to terminal alkynes is realized by using TBAF in THF which performance with retention of configuration The starting materials were synthesized by organometallic reagents. In summary,we have developed a cobalt-catalyzed asymmetric 1,4-addition of (t-buthyldiphenylsilyl)-acetylene to cyclo-1,3-dienes compounds in high yields with high regioselectivity and high enantioselectivity.
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