The first asymmetric decarboxylative [4 + 3] annulation of propargylic carbamates with C, N-cyclic azomethineimines has been developed successfully by a copper- N-heterocyclic carbine system. This strategy led to a series of optically active isoquinoline-fused triazepine derivatives in good yields and with excellent enantio- and diastereoselectivities. Remarkably, Cu-allenylidene intermediates play
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
Chiral Phosphoric Acid-Catalyzed Enantioselective Formal [3+2] Cycloaddition of Azomethine Imines with Enecarbamates
作者:Yang Wang、Qian Wang、Jieping Zhu
DOI:10.1002/chem.201601548
日期:2016.6.6
The first catalytic asymmetric inverse electron demand 1,3‐dipolar cycloaddition of azomethine imines with enecarbamates has been developed. Isoquinoline‐fused pyrazolidines containing two or three contiguous stereogenic centers were obtained in high yields with excellent regio‐, diastereo‐, and enantioselectivities. The pyrazolidine ring can be opened to install an aminal, α‐amino nitrile, or homoallylamine
CuBr2 catalyzed bromination/oxidation of isochromans to benzaldehyde derivatives
作者:Mei-Yan Zhou、Shan-Shan Kong、Ling-Qiong Zhang、Ming Zhao、Jin-Ao Duan、Zhen Ou-yang、Min Wang
DOI:10.1016/j.tetlet.2013.05.078
日期:2013.7
A series of isochromans were oxidized and brominated by using 1.2 equiv of CuBr2 in CH3CN at reflux to give the corresponding bromo benzaldehydes in moderate yields. A plausible mechanism for this transformation has been suggested. (C) 2013 Elsevier Ltd. All rights reserved.
Ytterbium-Catalyzed Intramolecular [3 + 2] Cycloaddition based on Furan Dearomatization to Construct Fused Triazoles
development of expeditious methods to synthesize these skeletons remains a challenging task. In this work, the catalyticcyclization of biomass-derived 2-furylcarbinols with an azide to form fused triazoles is described. This approach takes advantage of a single catalyst Yb(OTf)3 and operates via a furfuryl-cation-induced intramolecular [3 + 2] cycloaddition/furan ring-opening cascade.