Selective Transformation of β-Disubstituted Enones and Ynones in the Presence of β-Monosubstituted Enones
Selective Transformation of β-Disubstituted Enones and Ynones in the Presence of β-Monosubstituted Enones
复制标题
β-单取代烯酮存在下 β-二取代烯酮和 Ynon 的选择性转化
DOI：
10.1002/ajoc.201700711
复制
发表时间：
2018
影响因子：
2.7
通讯作者：
Fujioka Hiromichi
中科院分区：
文献类型：
--
作者：
Morita Kenta;Ohta Reiya;Watanabe Kei;Fujioka Hiromichi
α,β-不饱和羰基存在于许多天然产物和功能分子中。亲核试剂对 α,β-不饱和羰基（例如 β-单取代和二取代的 α,β-不饱和酮（烯酮）和炔酮）的反应性相似。因此，开发一种选择性转化α,β-不饱和羰基的方法是值得的。在本研究中，使用原位保护方法在 β-单取代烯酮存在下完成了 β-二取代烯酮或炔酮的选择性一锅还原和烯丙基化。 β-单取代烯酮在β-二取代烯酮或炔酮存在下选择性地与三苯基膦和三甲基硅基三氟甲磺酸酯的组合反应，生成鏻硅基烯醇醚，其在剩余β-二取代烯酮或炔酮的还原和烯丙基化过程中充当烯酮保护基。然后在后处理中很容易将底物脱保护以再生母体烯酮。
α,β‐Unsaturated carbonyl groups are found in many natural products and functional molecules. The reactivity of nucleophiles towards α,β‐unsaturated carbonyls, such as β‐monosubstituted and disubstituted α,β‐unsaturated ketones (enones) and ynones, is similar. Therefore, the development of a method to selectively convert α,β‐unsaturated carbonyls is desirable. In this study, selective one‐pot reductions and allylations of β‐disubstituted enones or ynones were accomplished in the presence of β‐monosubstituted enones using an in situ protection methodology. β‐Monosubstituted enones selectively reacted with a combination of triphenylphosphine and trimethylsilyl triflate in the presence of β‐disubstituted enones or ynones to produce phosphonium silyl enol ethers, which acted as enone protecting groups during the reduction and allylation of the remaining β‐disubstituted enone or ynone. The substrate was then easily deprotected in the workup to regenerate the parent enone.