A new mode of aromatic metamorphosis has been developed, which allows thiophenes and their benzo‐fused derivatives to be converted to a variety of exotic heteroles. This transformation involves 1) the efficient generation of key 1,4‐dianions by means of desulfurative dilithiation with lithium powder and 2) the subsequent trapping of the dianions with heteroatom electrophiles in a one‐pot manner. Via
1-Silaindenes are prepared starting from (2-vinylphenyl)hydrosilanes and alkynes through a ruthenium-catalyzed hydrosilylation-ring-closing-metathesis sequence. The method is successfully applied to the synthesis of molecules containing multiple silaindene units.
Synthesis of Benzo[<i>b</i>]siloles via KH-Promoted Cyclization of (2-Alkynylphenyl)silanes
作者:Laurean Ilies、Hayato Tsuji、Eiichi Nakamura
DOI:10.1021/ol9015282
日期:2009.9.3
(2-Alkynylphenyl)silanes undergo intramolecular cyclization in the presence of an excess or a subequimolar amount of potassium hydride to give a variety of new 2-substituted benzosiloles in good to excellent yields. Some of these compounds showed a high fluorescence quantum yield both in solution and in the solid state, and they also showed reversible reduction in THF.
partially or fully fused ladder oligo(p-phenylenevinylene)s (LOPVs) and related π-electron systems has been synthesized. Thus, the intramolecular reductive cyclization of o-silyl-substituted bis(phenylethynyl)benzenes with lithium naphthalenide produces partially silicon-bridged bis(styryl)benzenes consisting of silaindene or disilaindacene skeletons. By combining this cyclization with the Friedel–Crafts type
[reaction: see text] The reaction of (o-silylphenyl)acetylene derivatives with lithium naphthalenide undergoes intramolecular reductivecyclization to produce various silaindene derivatives. On the basis of this methodology, a series of silaindene-containing pi-electron systems are synthesized that show intense blue to greenish-blue fluorescence.