Direct synthesis of pyrroles via 1,3-dipolar cycloaddition of azomethine ylides with ynones
作者:Zheng Wang、Ying Shi、Xiaoyan Luo、De-Man Han、Wei-Ping Deng
DOI:10.1039/c3nj00067b
日期:——
A direct and facile synthesis of multi-substituted pyrroles via AgOAc-catalyzed 1,3-dipolarcycloaddition of azomethine ylides with ynones is developed, providing the corresponding adducts in moderate to high yields (up to 89%).
In this work, we introduced a multifunctional Ag(I)/CAAA-amidphos complex catalyzed asymmetric 1,3-dipolarcycloaddition of acrylates with α-imino esters, affording a series of 2,4,5-trisubstituted endo-pyrrolidines in good yields (up to 97%) with high enantioselectivities (up to 98% ee). Meanwhile, the catalytic system was also applied in the three-component one-pot reaction of α-imino esters formed
Reactions of fluorobenzene tricarbonylchromium complexes with anions from Schiff bases of α-amino esters; enantioselective synthesis of α-aryl amino acids
We report here a convenient synthesis of α-substituted aryl amino acids via the addition of α-amino esters to fluorobenzene tricarbonylchromium complexes. Optically pure α-aryl amino acids have been prepared by enantioselective substitution of fluorobenzene complexes using Schiff bases of L-alanine, leucine and valine methyl esters and (1R,2R,5R)-2-hydroxypinan-3-one.
The l -tert-leucine-derived AmidPhos/silver(I) catalytic system has been developed for the asymmetric [3+2] cycloaddition of azomethineylides with electronic-deficient alkenes with or without Et3N. Under optimal conditions, highly functionalized endo-4-pyrrolidines were obtained with modest to high yields (up to 99% yield) and enantioselectivities (up to 98% ee).
Catalytic asymmetric 1,3-dipolar cycloaddition of N-unprotected 2-oxoindolin-3-ylidene derivatives and azomethine ylides for the construction of spirooxindole-pyrrolidines
作者:Tang-Lin Liu、Zhi-Yong Xue、Hai-Yan Tao、Chun-Jiang Wang
DOI:10.1039/c0ob00943a
日期:——
Asymmetric 1,3-dipolar cycloaddition of N-unprotected 2-oxoindolin-3-ylidene with azomethine ylides for the construction of spirooxindole-pyrrolidines bearing four contiguous stereogenic centers has been achieved with AgOAc/TF-BiphamPhos complexes for the first time. This catalytic system performance well over a broad scope of substrates, providing the synthetically useful adducts in high yields and excellent diastereoselectivities and moderate enantioselectivities.