使用顺磁性钴(II)卟啉催化剂[Co II (TPP)](TPP=四苯基卟啉)对邻烯丙基羰基-芳基N-芳基磺酰腙进行金属自由基活化,为合成新型8元杂环化合物提供了一种有效且强大的方法烯醇醚。该合成方案通用且实用,能够以高产率合成多种独特的 1 H -2-苯并氧辛。催化环化反应具有优异的化学选择性,具有较高的官能团耐受性,并为合成新的生物活性化合物提供了多种机会。该反应通过钴(III)-卡宾自由基中间体进行,该中间体参与从烯丙基位置到卡宾自由基的分子内氢转移(HAT),然后在钴的配位层中进行近无障碍的自由基反弹步骤。所提出的机制得到了实验观察、密度泛函理论(DFT)计算和自旋捕获实验的支持。
The enantioselectiveintermolecular cross Rauhut-Currierreaction of acrolein with active olefins has been a long-standing challenge because of competitive MBH reaction and polymerization. Reported herein is a highly enantioselectiveintermolecular...
Cooperative Heterobimetallic Zinc/Alkaline Earth Metal Catalysis: A Zn/Sr Aminophenol Sulfonamide Complex for Catalytic Asymmetric Michael Addition of 3-Acetoxy-2-oxindoles to β-Ester Enones
A heterobimetallic zinc/strontium catalyst has been developed for the asymmetric Michael addition of 3-acetoxy-2-oxindoles to β-ester enones in high yields with excellent enantioselectivities and high diastereoselectivities. This process represents that 3-acetoxy-2-oxindoles can be used as a stable air- and base-tolerant precursor for chiral 3-substituted 3-hydroxy-2-oxindoles.