Desymmetrization of the divinyl carbinol 1,4‐pentadien‐3‐ol was accomplished by the asymmetric 1,3‐dipolar cycloaddition of azomethine imines based on a magnesium‐mediated, multinucleating chiralreaction system utilizing diisopropyl (R,R)‐tartrate as the chiralauxiliary. The corresponding optically active trans‐pyrazolidines, each with three contiguous stereogenic centers, were obtained with excellent
The asymmetric 1,3-dipolar cycloaddition of azomethineimines to homoallylic alcohols was achieved by utilizing diisopropyl (R,R)-tartrate as a chiral auxiliary to give the corresponding optically active trans-pyrazolidines with excellent regio-, diastereo-, and enantioselectivities. The catalytic use of diisopropyl (R,R)-tartrate was also effective in the presence of MgBr 2 .
The asymmetric1,3-dipolarcycloaddition of azomethine imines to allyl alcohol was achieved by utilizing diisopropyl (R,R)-tartrate as a chiral auxiliary to afford the corresponding optically activ...
Catalytic Asymmetric 1,3-Dipolar Cycloaddition of Two Different Ylides: Facile Access to Chiral 1,2,4-Triazinane Frameworks
作者:Min-Chao Tong、Xuan Chen、Hai-Yan Tao、Chun-Jiang Wang
DOI:10.1002/anie.201306300
日期:2013.11.18
Ylides at a crossing: An unprecedented 1,3‐dipolar cycloaddition (cross‐cycloaddition) between twodifferentylides (see scheme) was realized by using the chiral CuI/tBu‐Phosferrox complex as the catalyst under mild reaction conditions. This catalytic system provides an expeditious approach to the construction of highly functionalized 1,2,4‐triazinane derivatives in good yields with excellent diastereoselectivities
交叉点处的耶利德:在温和的反应条件下,通过使用手性Cu I / t Bu-Phosferrox配合物作为催化剂,实现了两个不同的耶利德之间前所未有的1,3-偶极环加成(交叉环加成)(参见方案)。该催化体系为构建高官能度的1,2,4-三氮杂烷衍生物提供了一种快速的方法,该衍生物具有良好的收率和出色的非对映选择性和对映选择性。
An Efficient Copper-mediated 1,3-Dipolar Cycloaddition of Pyrazolidinone-based Dipoles to Terminal Alkynes to Produce<i>N</i>,<i>N</i>-Bicyclic Pyrazolidinone Derivatives
A simple dinuclear copper complex [Cu(μ-OH)(tmen)]2Cl2 (tmen = N,N,N′,N′-tetramethylethylenediamine) could act as an effective precatalyst for the 1,3-dipolar cycloaddition of pyrazolidinone-based dipoles to terminal alkynes to produce the corresponding N,N-bicyclic pyrazolidinone derivatives.