α-Diazoacetates as Carbene Precursors: Metallosalen-Catalyzed Asymmetric Cyclopropanation
作者:Tsutomu Katsuki、Tatsuya Uchida
DOI:10.1055/s-2006-926448
日期:2006.5
Readily available α-diazo compounds have been shown to be efficient carbene precursors for asymmetric cyclopropanation using ruthenium(NO)-salen and cobalt-salen complexes, as catalysts. The stereoselectivity of the cyclopropanation depends on the metal ion, its valency, the structural and electronic nature of the salen ligand, and the apical ligand of the salen complex used. Both trans- and cis-selective asymmetric intermolecular cyclopropanation can be realized under mild conditions by using a suitable metallosalen complex. Furthermore, a wide range of alkenyl α-diazoacetates and the related alkenyl diazomethyl ketones undergo intramolecular cyclopropanation in a highly enantioselective manner by using various metallosalen complexes, easily prepared in a modular fashion, as catalyst.
Stereodivergent Intramolecular Cyclopropanation Enabled by Engineered Carbene Transferases
作者:Ajay L. Chandgude、Xinkun Ren、Rudi Fasan
DOI:10.1021/jacs.9b02700
日期:2019.6.12
myoglobin biocatalysts for executing asymmetric intramolecular cyclopropanations resulting in cyclopropane-fused γ-lactones, which are key motifs found in many bioactive molecules. Using this strategy, a broad range of allyl diazoacetate substrates were efficiently cyclized in high yields with up to 99% enantiomeric excess. Upon remodeling of the active site via protein engineering, myoglobin variants
Intramolecular Asymmetric Cyclopropanation with (Nitroso)(salen)ruthenium(II) Complexes as Catalysts
作者:Biswajit Saha、Tatsuya Uchida、Tsutomu Katsuki
DOI:10.1055/s-2001-9733
日期:——
Intramolecular cyclopropanation of (E)-2-alkenyl-α-diazoacetates was carried out with good to high enantioselectivity by using (nitroso)(salen)ruthenium(II) complexes as catalysts under photo-irradiation.
Enantioselective Intramolecular Iridium-Catalyzed Cyclopropanation of α-Carbonyl Sulfoxonium Ylides
作者:Lucas Vidal、Pan-Pan Chen、Eva Nicolas、Andrew Hackett、Craig M. Robertson、Kendall N. Houk、Christophe Aïssa
DOI:10.1021/acs.orglett.2c03396
日期:2022.11.25
Enantioselective cyclopropanation of α-carbonyl sulfoxonium ylides (SY) has so far been limited to addition/ring closure reactions on electron-poor olefins. Herein, we report the iridium-catalyzed intramolecular cyclopropanation of SY in the presence of a chiral diene in up to 96% yield and 98% enantioselectivity. Moreover, density functional theory calculations suggest that the re face of the olefin
迄今为止,α-羰基亚砜 (SY) 的对映选择性环丙烷化仅限于缺电子烯烃的加成/闭环反应。在此,我们报道了在手性二烯存在下铱催化的 SY 分子内环丙烷化反应,收率高达 96%,对映选择性高达 98%。此外,密度泛函理论计算表明,烯烃的表面优选在与烯烃的几何结构无关的异步协同步骤中攻击铱卡宾中间体。
Chiral Bis(pyridylimino)isoindoles: A Highly Modular Class of Pincer Ligands for Enantioselective Catalysis