Acetylene derivs silylacetylenes

Ethylene from acetylene derivatives with protection of terminal carbon-carbon triple bonds as silylacetylenes... 

In a cross-coupling reaction of 3- or 4-chloropyridazines and trimethyl-silylacetylene in the presence of Pd(PPh3)2Cl2-CuI as catalyst, the tri-methylsilyl derivatives were obtained (82S312). The same transformation with monosubstituted acetylenes afforded 3-alkynylpyridazines or their... 

Reactions with butyllithium/tetramethylenediamine Silylacetylenes from halides Protection of terminal acetylene groups as trimethylsilyl derivatives... 

Further work from Vollhardt s group on cobalt-catalysed cycloadditions of olefins and acetylenes has led to a synthesis of cyclohexadiene derivatives (188 n = 0—2) by addition of trimethyl silylacetylenes the reactions can also be carried out in an intramolecular sense, leading to tricyclic compounds. The novel tricyclic compound (189) has been obtained from naphthoquinone by a [2 + 2]addition of l,l-bis(silylmethyl)ethylene followed by treatment with a Lewis acid. A key step in the first total synthesis of a decipiene diterpene is the formation of tricyclic ketone (190) by an intramolecular aldol condensation, which required the use of methanolic barium oxide. ... 

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