Substituted Oxocanes by Intramolecular Allylboration Reactions. Entry to an Efficient Synthesis of (+)-Laurencin
作者:Jochen Krüger、Reinhard W. Hoffmann
DOI:10.1021/ja970914u
日期:1997.8.1
such as cis-3-hydroxy-2-vinyl-Δ5-oxocenes, can be generated by an intramolecular aldehyde−allylboration reaction. This allowed a rapid and stereoselective access to the trisubstituted oxocene 24 which had been transformed by the Holmes group into (+)-laurencin. The key feature of this effective intramolecular allylboration reaction is that both the aldehyde and the allylboronate functionality have
Δ5-Oxocenes,如 cis-3-hydroxy-2-vinyl-Δ5-oxocenes,可以通过分子内醛-烯丙基硼化反应生成。这允许快速和立体选择性地访问已被 Holmes 小组转化为 (+)-laurencin 的三取代氧新烯 24。这种有效的分子内烯丙基硼化反应的关键特征是醛和烯丙基硼酸酯官能团都以掩蔽形式原位生成。它们通过引发闭环反应的水性后处理释放。