Tuning Reactivity and Chemoselectivity in Electron Transfer Initiated Cyclization Reactions: Applications to Carbon−Carbon Bond Formation
作者:John R. Seiders、Lijun Wang、Paul E. Floreancig
DOI:10.1021/ja029139v
日期:2003.3.1
demonstrate that the scope of our electrontransfer initiated cyclization reaction can be significantly broadened by exploiting the relationship between the oxidation potentials of homobenzylic ethers and the mesolytic benzylic carbon-carbonbond dissociation energies of their radical cations. By lowering the oxidation potential of the electrophore and the benzylic carbon-carbonbond dissociation energy, we
Synthesis of the C<sub>1</sub>-C<sub>15</sub> Fragment of Apicularen A through a Regioselective Electron-Transfer-Initiated Cyclization Reaction
作者:Paul Floreancig、Alexander Poniatowski
DOI:10.1055/s-2007-983776
日期:2007.7
bility for the use of oxidative cleavage to generate electro- philes throughcarbon-carbonbondactivation in the presence of acid-sensitive groups, and through acetal acti- vation in the presence of homobenzylic ethers and amides. We have reported several examples in which oxocarbeni- um and acyliminiumions can be formed through oxida- tive cleavage in the presence of acid-sensitive acetals 2 and
在本文中,我们报告了通过氧化环化方案制备液泡 ATP 酶抑制剂 apicularen A 的苄基四氢吡喃片段。在该反应中,在另一种高苄基醚存在下,一种高苄基醚的区域选择性裂解是通过取代选择性地弱化一个碳-碳 s 键来实现的。这项工作表明,即使在存在其他容易氧化的基团的情况下,只要在氧化后键断裂足够快,氧化断裂反应也可用于选择性地产生稳定的阳离子。在另一个结构相似的基团存在下选择性地激活一个官能团进行反应是复杂分子合成的重大挑战。解决这个问题的方法可以利用反应性或空间环境的细微差异,但更通常依赖于使用延长合成方案的保护基团。另一种方法是使用具有正交反应模式的官能团作为反应中间体的前体。我们通过在制备稳定的碳正离子中使用自由基阳离子碎裂反应对这种方法进行了广泛的研究。1 这些过程通过高苄基醚和酰胺的单电子氧化进行,这些醚和酰胺对通常用于形成碳正离子的酸性条件是完全惰性的。此外,缩醛等常见的阳离