Enantioselective Thiourea-Catalyzed Additions to Oxocarbenium Ions
作者:Sarah E. Reisman、Abigail G. Doyle、Eric N. Jacobsen
DOI:10.1021/ja801514m
日期:2008.6.1
Asymmetric, catalytic reactions of oxocarbeniumions are reported. Simple, chiral urea and thiourea derivatives are shown to catalyze the enantioselective substitution of silyl ketene acetals onto 1-chloroisochromans. A mechanism involving anion binding by the chiral catalyst to generate a reactive oxocarbeniumion is invoked. Catalysts bearing tertiary benzylic amide groups afforded highest enantioselectivities
A phosphane‐catalyzed [3+3] annulation of azomethineimines with ynones has been developed. Under mild reaction conditions, the reaction proceeds smoothly to afford tricyclic dinitrogen‐fused heterocyclic compounds in moderate to excellent yields with moderate to excellent stereoselectivies. Using a chiral phosphine as the catalyst, the reaction could work to give the cycloadduct in moderate yield
Synthesis of 5,6‐Dihydropyrazolo[5,1‐
<i>a</i>
]isoquinoline and Ethyl (
<i>Z</i>
)‐3‐Acetoxy‐3‐tosylpent‐4‐enoate through Tertiary‐Amine‐Catalyzed [3+2] Annulation
作者:Yu Lei、Jiao‐Jiao Xing、Qin Xu、Min Shi
DOI:10.1002/ejoc.201600577
日期:2016.7
catalyzed divergent [3+2] annulation of C,N-cyclic azomethineimines with δ-acetoxyallenoates was developed; 5,6-dihydropyrazolo[5,1-a]isoquinolines and ethyl (Z)-3-acetoxy-3-tosylpent-4-enoates were afforded in moderate to good yields in a one-pot manner under mild conditions. This annulation reaction provides a highly efficient method to construct dinitrogen-fusedheterocycles and ethyl (Z)-3-ace
A Phosphine-Catalyzed Novel Asymmetric [3+2] Cycloaddition of C,N-Cyclic Azomethine Imines with δ-Substituted Allenoates
作者:De Wang、Yu Lei、Yin Wei、Min Shi
DOI:10.1002/chem.201405191
日期:2014.11.17
asymmetric [3+2] cycloadditions of C,N‐cyclic azomethine imines with δ‐substituted allenoates have been developed in the presence of (S)‐Me‐f‐KetalPhos, affording functionalized tetrahydroquinoline frameworks in good yields with high diastereo‐ and good enantioselectivities under mild condition. The substrate scope has been also examined. This is the first time that δ‐substituted allenoates have been
作者:Saira Qurban、Yu Du、Jun Gong、Shao-Xia Lin、Qiang Kang
DOI:10.1039/c8cc08275h
日期:——
An asymmetric [3+2] cycloaddition of C,N-cyclic azomethine imines with α,β-unsaturated 2-acyl imidazoles catalyzed by a chiral-at-metal rhodiumcomplex has been developed. The corresponding C-1-substituted tetrahydroisoquinoline derivatives were obtained in high yields (>90%) with excellent stereoselectivities (up to 99% ee and >20 : 1 dr). The reaction can be conducted on a gram-scale using a low