Oxasilacyclopentanes as intermediates for silicon tethered ene cyclisations
作者:Jeremy Robertson、Donald S Middleton、Garry O'Connor、Tsarina Sardharwala
DOI:10.1016/s0040-4039(97)01818-2
日期:1998.2
Oxasilacyclopentanes 3, generated by either free-radical cyclisation, intramolecular hydrosilylation, or silicon tethered Diels-Alder reaction, may be efficiently opened with 2-propenyl-lithium and the product alcohols oxidised to prepare precursors 2 for silicontethered ene cyclisation. Efficient and highly stereoselective ene reactions have been achieved with these precursors.
Stereoselective Synthesis of Silacyclohexanols by Silicon Tethered Type II Ene Cyclisation
作者:Jeremy Robertson、Garry O'Connor、Tsarina Sardharwala、Donald S. Middleton
DOI:10.1016/s0040-4020(00)00737-7
日期:2000.10
silane precursors for intramolecular ene reaction were prepared either by sequential organometallic substitution of appropriate silyl halides or by ring opening of oxasilacyclopentanes with 2-propenyllithium. The oxasilacyclopentane intermediates were prepared by free-radicalcyclisation, intramolecular hydrosilylation, or intramolecular Diels–Alder reaction. Treatment of the ene precursors with methylaluminium
Silicon Tethered Alkenyl Transfer and Type I Ene Reactions
作者:Jeremy Robertson、Garry O'Connor、Caroline L. Ringrose、Donald S. Middleton
DOI:10.1016/s0040-4020(00)00738-9
日期:2000.10
effecting silicon tethered Type I ene cyclisations analogous to our previously reported Type II variant. Some of these substrates were found to undergo overall stereospecific alkenyl transfer via silacyclopentanol intermediates; in a homologous series, alkenyl transfer was accompanied by dehydration to provide 7-silylhepta-2,4-dienes in moderate yield. Formal Type I ene cyclisations were found to be