A diastereo- and enantioselective propargylic substitution reaction between propargylic carbonates and α-substituted nitroacetates catalyzed by a Cu-pybox complex is described. This method allows the preparation of a series of non-proteinogenic quaternary α-aminoacid precursors featuring two contiguous stereogenic centers and a terminal alkyne moiety in high yields with good to excellent diastereo-
Enantioselective Synthesis of Highly Functionalized Dihydrofurans through Copper-Catalyzed Asymmetric Formal [3+2] Cycloaddition of β-Ketoesters with Propargylic Esters
作者:Fu-Lin Zhu、Ya-Hui Wang、De-Yang Zhang、Jie Xu、Xiang-Ping Hu
DOI:10.1002/anie.201405857
日期:2014.9.15
An enantioselectivesynthesis of highly functionalized dihydrofurans through a copper‐catalyzed asymmetric [3+2] cycloaddition of β‐ketoesters with propargylic esters has been developed. With a combination of Cu(OTf)2 and a chiral tridentate P,N,N ligand as the catalyst, a variety of 2,3‐dihydrofurans bearing an exocyclic double bond at the 2 position were obtained in good chemical yields and with
Enantioselective Copper-Catalyzed Propargylic Etherification of Propargylic Esters with Phenols Promoted by Inorganic Base Additives
作者:Long Shao、De-Yang Zhang、Ya-Hui Wang、Xiang-Ping Hu
DOI:10.1002/adsc.201600284
日期:2016.7.28
An enantioselectivecopper‐catalyzed propargylic etherification of both aromatic and aliphatic propargylic esters with phenols has been developed, in which the employment of inorganic base additives, in particular cesium carbonate (Cs2CO3), was found to significantly promote not only the reactivity but also the enantioselectivity of the reaction. By using a structurally hindered chiral ketimine P,N
已经开发出芳香族和脂肪族炔丙基酯与酚的对映选择性铜催化的炔丙基醚化,其中发现使用无机碱添加剂,特别是碳酸铯(Cs 2 CO 3),不仅可以显着提高反应性,而且可以显着提高活性。以及反应的对映选择性。通过使用结构受阻的手性酮亚胺P,N,N-配体,可以高收率和极好的对映选择性(高达98%ee)制备各种光学活性的炔丙基醚。
Highly enantioselective copper-catalyzed propargylic amination to access <i>N</i>-tethered 1,6-enynes
A highly enantioselective copper-catalyzed propargylic amination starting from benzylicallylic amines has been developed with a new chiral N,N,P ligand. A series of N-tethered 1,6-enynes were synthesized in good to excellent yields with excellent enantioselectivities. Utilization of transition metal-catalyzed cycloisomerization of 1,6-enynes provides several enantioselectively enriched chiral five-membered
Herein, a copper catalyzed asymmetric propargylation of 2-oxindole-3-carboxylate esters with terminal propargylic esters is described. This strategy successfully provides a direct approach to constructing a broad range of chiral C3-tetrasubstituted oxindoles with contiguous tertiary and quaternary carbon stereocenters in high yields and excellent enantioselectivities (16 examples, up to 99% yield and