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。
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。
C7‐Functionalization of Indoles via Organocatalytic Enantioselective Friedel‐Crafts Alkylation of 4‐Amino‐ indoles with 2‐Butene‐1,4‐diones and 3‐Aroylacrylates
作者:Tongkun Huang、Yunlong Zhao、Shanshui Meng、Albert S. C. Chan、Junling Zhao
DOI:10.1002/adsc.201900377
日期:2019.8.5
An efficient protocol for the enantioselective C7 Friedel‐Crafts alkylation between 4‐aminoindoles and 2‐butene‐1,4‐diones or 3‐aroylacrylates was reported. This process was catalyzed by a chiral phosphoric acid, affording the corresponding 1,4‐disubstituted indoles in moderate to high yields with good to high enantioselectivities. This reaction could be performed on a gram scale without loss of efficiency
Organophosphine bearing multiple hydrogen-bond donors for asymmetric Michael addition reaction of 1-oxoindane-2-carboxylic acid ester via dual-reagent catalysis
phosphines derived from dipeptide dual-reagents catalyzed asymmetric Michael addition reactions between indene esters and activated olefins in high yields and good to excellent enantioselectivities under mild reaction conditions. The success of current highly selective reactions should provide inspiration for expansion to other reactions and would open up new paradigms for the synthesis of indanone derivatives
Highly Enantioselective Michael Addition of Pyrazolin-5-ones Catalyzed by Chiral Metal/N,N′-Dioxide Complexes: Metal-Directed Switch in Enantioselectivity
Make the switch: The first example of a switch in enantioselectivity in the asymmetric Michaeladdition of pyrazolin‐5‐ones to 4‐oxo‐4‐arylbutenoates that is controlled by the metal center of the catalyst is reported. By using the same N,N′‐dioxide ligand L with different metals the respective enantiomers of various 4‐substituted 5‐pyrazolone derivatives were obtained. Tf=trifluoromethanesulfonyl.
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.
Squaramide-catalyzed asymmetric Michael/cyclization of 4-isothiocyanato pyrazolones and α,β-unsaturated ketones
作者:Wenjing Gong、Xin Du、Wenyao Wang、Wande Zhang、Baomin Wang
DOI:10.1016/j.tetlet.2021.153259
日期:2021.8
The cascade Michaeladdition/cyclization reaction of 4-isothiocyanato pyrazolones with ethyl β-benzoylacrylates has been explored by asymmetric organocatalysis, delivering spiro[pyrazolone-pyrrolidinethione] cores bearing three contiguous stereogenic centers in excellent enantioselectivities (up to 95% ee) with excellent yields (up to 91%). This process exhibited broad substrate scope and the advantages