Design, synthesis and application of a new type of bifunctional Le-Phos in highly enantioselective γ-addition reactions of N-centered nucleophiles to allenoates
作者:Haile Qiu、Xiaofeng Chen、Junliang Zhang
DOI:10.1039/c9sc04073k
日期:——
A novel class of bifunctional cyclic phosphine catalysts (Le-Phos) is reported, which showed good performances in enantioselective γ-addition reactions of N-centered nucleophiles and allenoates under mild conditions.
nucleophilic catalyst for umpolung addition of azoles to electron-deficient allenes. This strategy offers a simple and efficient method for functional allylation of azoles under neutral conditions and affords heterocyclic substituted Michaelolefins. Furthermore, this catalytic methodology has been extended to addition–cyclization reactions between electron-deficient allenes or alkynes and pyrrole-2-carboxaldehyde
Multicomponent Reaction of Imidazo[1,5-<i>a</i>]pyridine Carbenes with Aldehydes and Dimethyl Acetylenedicarboxylate or Allenoates: A Straightforward Approach to Fully Substituted Furans
facile three-component reactions of N,N-substituted imidazo[1,5-a]pyridine carbenes, namely imidazo[1,5-a]pyridin-3-ylidenes, with aldehydes and DMAD or allenoates were disclosed. Both reactions proceeded via tandem nucleophilic addition, [3 + 2]-cycloaddition, and ring transformation to produce different 4-[(2-pyridyl)methyl]aminofuran derivatives generally in moderate yields. This work not only provided
公开了N,N-取代的咪唑并[1,5- a ]吡啶碳烯的简单的三组分反应,即咪唑并[1,5 - a ]吡啶-3-亚胺与醛和DMAD或脲基甲酸酯的反应。这两个反应都是通过串联亲核加成,[3 + 2]-环加成和环转化进行的,通常以中等收率产生不同的4-[((2-吡啶基)甲基]氨基呋喃衍生物。这项工作不仅提供了咪唑并[1,5 - a ]吡啶-3-吡咯烷在有机合成中的应用的第一个例子,而且还开发了一种直接取代完全呋喃的简单方法,而其他方法不易获得。
Divergent Phosphine-Catalyzed [2+4] or [3+2] Cycloaddition Reactions of γ-Substituted Allenoates with Oxadienes
作者:Erqing Li、Meijia Chang、Ling Liang、You Huang
DOI:10.1002/ejoc.201403369
日期:2015.2
of the phosphine catalysts, the γ-substitutedallenoates selectively acted as C3 or C2 synthons. Under the catalysis of different organophosphine catalysts, the domino reaction proceeded smoothly with broad substrate tolerance and excellent total yields. The results suggest that the ethyl group of the γ-substitutedallenoates played a key role in the domino reaction.
Phosphine-Catalyzed Domino Reactions: A Route to Functionalized Bicyclic Skeletons
作者:Erqing Li、You Huang
DOI:10.1002/chem.201304003
日期:2014.3.17
sequential [2+3] and [3+2] annulation reactions was developed. In this dominoreaction, γ‐substituted allenoates were used as novel C4 synthons, and the bicyclic cyclopenta[b]dihydrofuran derivatives were produced in good to excellent diastereoselectivities and yields under mild conditions. Furthermore, preliminary studies on an asymmetric variant of this reaction proceeded with moderate enantioselectivity
涉及膦催化的连续的[2 + 3]和[3 + 2]环反应的新策略的开发。在该多米诺反应,γ取代的联烯酸酯被用作新型C- 4个合成子,和双环环戊二烯并[ b ]是在良好至优异的非对映选择性和温和的条件下生成物的收率二氢呋喃衍生物。此外,在该反应的不对称变型初步研究进行适度的对映选择性。