[3 + 2]-Cycloadditions of Azomethine Imines and Ynolates
作者:Sarah E. Winterton、Joseph M. Ready
DOI:10.1021/acs.orglett.6b01104
日期:2016.6.3
A novel [3 + 2]-cycloaddition between azomethine imines and lithium ynolates is described to synthesize bicyclic pyrazolidinones. These bicyclic pyrazolidinones are versatile intermediates to form β-amino acids and monocyclic pyrazolidinones. High diastereoselectivity and stereospecificity allow access to optically active products.
A Novel One-Pot, Three-Component Synthesis of 5-Imino-2,3,5,8-tetrahydropyrazolo[1,2-a]pyridazin-1-one Derivatives
作者:Yong-Min Liang、Bo Qian、Ming-Jin Fan、Yong-Xin Xie、Lu-Yong Wu、Yun Shi
DOI:10.1055/s-0028-1088070
日期:2009.5
It was found that the zwitterionic intermediate obtained from the addition of isocyanides to dimethyl acetylenedicarboxylate could react with 1,3-dipolar compounds under mild conditions to produce 5-imino-2,3,5,8-tetrahydropyrazolo[1,2-a]pyridazin-1-one derivatives in high yields. A plausible mechanism was also discussed for this process.
Metal Amides as the Simplest Acid/Base Catalysts for Stereoselective Carbon-Carbon Bond-Forming Reactions
作者:Yasuhiro Yamashita、Shū Kobayashi
DOI:10.1002/chem.201300908
日期:2013.7.15
paper, new possibilities for metalamides are described. Although typical metalamides are recognized as strong stoichiometric bases for deprotonation of inert or less acidic hydrogen atoms, transition‐metalamides, namely silver and copper amides, show interesting abilities as one of the simplestacid/basecatalysts in stereoselectivecarbon–carbon bond‐forming reactions.
stereoselective [3 + 2] dipolar cycloadditions of azomethine imines with α,β-unsaturatedaldehydes catalyzed by readily available α,α-diarylprolinol salts are reported, providing a facile route to the synthesis of various chiral bipyrazolidin-3-one derivatives under mild conditions. The organocatalyst 1 g with strongly electron-withdrawing groups exhibited the best stereoselectivity (exo:endo up to 98:2, for exo
Thermal 1,3-dipolar cycloaddition of azomethine imines with alkynes affording N,N-bicyclic pyrazolidinones under microwave irradiation
作者:Zhi-Wei Yang、Jing-Fang Wang、Li-Jie Peng、Xiao-Lin You、Hai-Lei Cui
DOI:10.1016/j.tetlet.2016.10.030
日期:2016.11
A metal and catalyst free 1,3-dipolar cycloaddition reaction of azomethineimines with internal alkynes has been developed. Various N,N-bicyclic pyrazolidinones could be prepared quickly under microwave irradiation in moderate to excellent yields (up to 96%). A wide range of azomethineimines and electron-deficient internal alkynes were applicable to this reaction. In addition, gram-scale reaction