在本文中,我们描述了迈克尔受体与手性硫叶立德环丙烷化的研究。先前已经发现,半稳定的锍叶立德(例如,Ph-稳定的)与环状和非环状烯酮以及取代的丙烯酸酯反应,具有高 ee 并且稳定的锍叶立德(例如,酯稳定的)再次与具有高 ee 的环烯酮反应. 目前的研究集中在稳定的锍叶立德与无环烯酮的反应上,这些反应出乎意料地降低了 ee。此外,在与甲基乙烯基酮 (MVK) 的反应中观察到 ee 与叶立德稳定性的明显相关性:酮稳定的叶立德产生 25% ee,酯稳定的叶立德产生 46% ee,酰胺稳定的叶立德产生 89% ee。据信,甜菜碱形成后,会出现一个不寻常的质子转移步骤,这会损害该过程的对映选择性。因此,在将稳定的叶立德添加到迈克尔受体后,甜菜碱中间体内的快速和可逆的分子内质子转移,在闭环之前,导致 ee 的侵蚀。最稳定的叶立德(酮)发生最大程度的质子转移。当用氘标记的锍叶立德进行相同的反应时,在所有情况下都观察到更高的
作者:Jack E. Baldwin、Robert M. Adlington、Mark B. Mitchell、Jeremy Robertson
DOI:10.1016/s0040-4020(01)86541-8
日期:1991.7
The synthesis of 10–15 membered α-methylene macrocyclic lactones from the functionalised allylstannanes (7e)–(7j) is described. Attempts to synthesise analogous 6–9 membered lactones proved unsuccessful, resulting instead in the production of dilactones and AIBN derived adducts.
Introduction of Alkyl- or Phenylseleno Group by the Ring Opening of Cyclic Ethers Using Dialkyl- or Alkylphenylselenium Dibromide and Sodium Borohydride
Abstract The reaction of dialkyl- or alkylphenylselenium dibromide with cyclic ethers in the presence of sodiumborohydride gave ω-hydroxyalkyl alkyl or phenyl selenides as the ring opening products of the cyclic ethers.
Synthesis of spiroethers using radical cyclisations
作者:Donald S Middleton、Nigel S Simpkins、Michael J Begley、Nicholas K Terrett
DOI:10.1016/s0040-4020(01)85436-3
日期:1990.1
A variety of spiroether products, including one bis-spiro compound, are available via a simple radicalcyclisation route.
可通过简单的自由基环化途径获得多种螺醚产物,包括一种双螺化合物。
Radical reactions in synthesis: intramolecular SH2? macrocyclisations
作者:Jack E. Baldwin、Robert M. Adlington、Mark B. Mitchell、Jeremy Robertson
DOI:10.1039/c39900001574
日期:——
The synthesis of 10–15 membered α-methylene lactones 1 from the functionalised allyl stannanes 2 occurs cleanly in moderate to high yield under free radical conditions via an intramolecularSH2′ reaction.
由官能化的烯丙基锡烷2合成10-15元α-亚甲基内酯1可以在自由基条件下通过分子内S H 2'反应以中等至高收率干净地进行。
Preparation and palladium-mediated cross-coupling of α-benzoyloxyalkylzinc bromides
作者:Komei Sakata、Daisuke Urabe、Masayuki Inoue
DOI:10.1016/j.tetlet.2013.05.114
日期:2013.8
report a two-step preparation protocol of α-benzoyloxyalkylzinc bromides from α-benzoyloxyalkyl selenides, and their application to palladium-catalyzedcross-coupling reactions with aryl and vinyl iodides. The developed method effectively provides a variety of benzoyl-protected benzylic and allylic alcohol derivatives through the formation of C(sp3)–C(sp2) bonds without affecting various polar functional