2-Phenyliminomethylphenols, 2-phenylaminomethylphenols and their copper(II) complexes
作者:H.J. Harries、B.F. Orford、J. Burgess
DOI:10.1016/s0020-1693(00)88934-3
日期:1983.1
2-phenyliminomethylphenols (I) and 2-phenylaminomethylphenols (II) are described. Acid dissociation constants, determined potentiometrically, for the amines (II) are related to substituent constants; values are not obtained for Schiff bases(I) due to their hydrolysis. IR spectra of the amines (II) indicate chelate ring formation via OH⋯N hydrogen bonding. NMR spectra for Schiff bases (I) are consistent
The reactions of salicylaldimines with electron‐rich alkenes (2,3‐dihydro‐2H‐furan and 3,4‐dihydro‐2H‐pyran) catalyzed by N,N′‐dioxide–Sc(OTf)3complexes were investigated. The methodology was successfully applied to the asymmetricsynthesis of cis‐4‐aminobenzopyran derivatives. Excellent yields, diastereo‐ and enantioselectivities were observed for a broad range of substrates under mild conditions
Brønsted acids of anionic chiral Co(<scp>iii</scp>) complexes as catalysts for the stereoselective synthesis of cis-4-aminofuranobenzopyrans
作者:Hua-Jie Jiang、Kun Liu、Jing Wang、Na Li、Jie Yu
DOI:10.1039/c7ob02452e
日期:——
A highly enantioselective interrupted Povarov reaction of salicylaldimines and 2,3-dihydrofuran was developed, through the elegant Brønsted acid catalysis of anionic chiral Co(III) complexes. This reaction affords the cis-4-aminofuranobenzopyran derivatives with up to 95% yield, >20:1 dr and 96:4 er. Moreover, a one-pot three-component procedure of salicylaldehydes, anilines, and 2,3-dihydrofuran proves
A highly enantioselective synthesis of 3,4-diaminochroman-2-ones has been realized via the domino reaction of o-hydroxy aromatic aldimines and azlactones. Notably, a cis-product was obtained as the major product by the use of guanidine 2a whereas a trans-product was the major product with bisguanidium salt 3•HBArF4. In two cases, various substituted 3,4-dihydrocoumarins were obtained with high yields
通过邻羟基芳族醛亚胺和a内酯的多米诺反应,已经实现了对3,4-二氨基苯并二氢吡喃-2-酮的高度对映选择性的合成。值得注意的是,通过使用胍2a获得了顺式产物作为主要产物,而反式产物是双胍盐3•HBAr F 4的主要产物。在两种情况下,以高收率(高达99%),出色的对映选择性(高达99%ee)和非对映选择性(高达> 99:1顺式:反式和98:2 )获得了各种取代的3,4-二氢香豆素。反式:顺式,分别)在温和的反应条件下。
Catalytic Asymmetric Mannich-Ketalization Reaction: Highly Enantioselective Synthesis of Aminobenzopyrans
作者:Magnus Rueping、Ming-Yuan Lin
DOI:10.1002/chem.201000203
日期:2010.4.12
Domino catalysis: We have developed the first enantioselective domino Mannich–ketalization reaction of o‐hydroxy benzaldimines with electron‐rich alkenes (see scheme). The new reaction sequence provides an easy and direct access to optically pure 4‐aminobenzopyrans in good yields and with excellent enantiomeric ratios (up to e.r. 98:2).