Phosphine-Catalyzed α-Umpolung–Aldol Reaction for the Synthesis of Benzo[<i>b</i>]azapin-3-ones
作者:Kui Zhang、Lingchao Cai、Sooji Hong、Ohyun Kwon
DOI:10.1021/acs.orglett.9b01749
日期:2019.7.5
serves as a conduit for the construction of benzo[b]azepin-3-ones in good to excellent yields under mild conditions. The resulting 2-benzylidene moieties are formed exclusively in the E-configuration. Mechanistically, this unusual annulation occurs through a phosphine-catalyzed α-umpolung addition, followed by an aldol reaction. One of the benzo[b]azepin-3-one products was converted to the core structure
报道了一种新型膦催化的 2-磺酰胺苯甲醛和炔酮之间的分子间环化。该方法可作为在温和条件下以良好至优异的产率构建苯并[ b ]氮杂-3-酮的渠道。所得的2-亚苄基部分仅以E-构型形成。从机制上讲,这种不寻常的环化是通过膦催化的 α-umpolung 加成,然后是羟醛反应发生的。其中一种苯并[ b ]氮杂卓-3-酮产品被转化为3-氨基-[ a ]苯并氮杂卓-2-一-1-链烷酸的核心结构,其中许多充当血管紧张素转换酶抑制剂。
Convenient synthesis of arylpropargyl aldehydes and 4-aryl-3-butyn-2-ones from arylacetylenes and amide acetals
作者:Ka Young Lee、Mi Jung Lee、Saravanan GowriSankar、Jae Nyoung Kim
DOI:10.1016/j.tetlet.2004.04.193
日期:2004.6
The reaction of arylacetylenes 1 and N,N-dimethylformamide dimethylacetal (2a, DMF-DMA) afforded the corresponding arylpropargyl aldehydes 3 in moderate yields. Similarly, the reaction of 1 and N,N-dimethylacetamide dimethylacetal (2b, DMA-DMA) gave 4-aryl-3-butyn-2-ones 4.
Asymmetric hydrogenation is one of the most powerful methods for the preparation of single enantiomer compounds. However, the chemo- and enantioselective hydrogenation of the relatively inert unsaturated group in substrates possessing multiple unsaturated bonds remains a challenge. We herein report a protocol for the highly chemo- and enantioselective hydrogenation of conjugated enynes while keeping
不对称氢化是制备单一对映体化合物的最有效方法之一。然而,在具有多个不饱和键的底物中相对惰性的不饱和基团的化学和对映选择性氢化仍然是一个挑战。我们在此报告了共轭烯炔的高度化学和对映选择性氢化同时保持炔键完整的协议。机理研究表明,Co II 配合物的锌还原产生的伴随的 Zn 2+在启动合理的 Co I /Co III催化循环中起着关键作用。这种方法可以高效生成手性炔丙胺(高达 99.9 % ee 和 2000 S/C)和进一步有用的化学转化。
Chemoselective P(NMe<sub>2</sub>)<sub>3</sub>-Mediated Reductive Epoxidation between Two Different Carbonyl Electrophiles: Synthesis of Highly Functionalized Unsymmetrical Epoxides
作者:Rong Zhou、Honghui Zhang、Jialin Liu、Rongfang Liu、Wen-Chao Gao、Yan Qiao、Ruifeng Li
DOI:10.1021/acs.joc.8b00995
日期:2018.8.3
α-diketones with aldehydes and ketones, leading to an efficient synthesis of a wide range of highly functionalized unsymmetrical epoxides in moderate to excellent yields and diastereoselectivities. The Kukhtin–Ramirez adduct, which is exclusively generated in situ from an α-dicarbonyl compound and P(NMe2)3, plays a key role in governing the chemoselectivity. It represents the first practical synthesis of unsymmetrical
Gold-catalyzed N,O-functionalization of 1,4-diyn-3-ols with <i>N</i>-hydroxyanilines to form highly functionalized pyrrole derivatives
作者:Yu-Chen Hsu、Shu-An Hsieh、Po-Hsuan Li、Rai-Shung Liu
DOI:10.1039/c8cc00330k
日期:——
This work describes new N,O-functionalization of 1,4-diyn-3-ols with N-hydroxyanilines to yield highlyfunctionalized pyrrole derivatives. In a postulated mechanism, N-hydroxyaniline attacks the more electron-rich alkynes via regioselective N-attack to form unstable ketone-derived nitrones that react with their tethered alkynes via an intramolecular oxygen-transfer to form α-oxo gold carbenes. This