A mild rhodium catalytic system has been developed to synthesize vinylcyclopropa[b]indolines through cyclopropanation of indoles with vinyl carbenoids generated from ringopening of cyclopropenes in situ. By employing a Rh-migration strategy, the products can be obtained with good to excellent E:Z ratios (≤99:1) and complete diastereoselectivity (≤99:1). This method is easy, has a low catalyst loading
已开发出一种温和的铑催化体系,通过将吲哚与原位环丙烯开环生成的乙烯基类胡萝卜素进行环丙烷化,来合成乙烯基环丙烷[ b ]二氢吲哚。通过采用Rh迁移策略,可以获得具有良好或优异的E:Z比(≤99:1)和完全非对映选择性(≤99:1)的产物。该方法容易,催化剂负载低并且适用于广泛的功能。
Asymmetric Nitrone Synthesis via Ligand-Enabled Copper-Catalyzed Cope-Type Hydroamination of Cyclopropene with Oxime
We report realization of the first enantioselective Cope-type hydroamination of oximes for asymmetric nitrone synthesis. The ligand promoted asymmetriccyclopropene “hydronitronylation” process employs a Cu-based catalytic system and readily available starting materials, operates under mild conditions and displays broad scope and exceptionally high enantio- and diastereocontrol. Preliminary mechanistic
Diastereoselectivity Control in Formal Nucleophilic Substitution of Bromocyclopropanes with Oxygen- and Sulfur-Based Nucleophiles
作者:Joseph E. Banning、Anthony R. Prosser、Bassam K. Alnasleh、Jason Smarker、Marina Rubina、Michael Rubin
DOI:10.1021/jo200368a
日期:2011.5.20
diastereoconvergent formal nucleophilicsubstitution of bromocyclopropanes with oxygen- and sulfur-based nucleophiles is described. The reaction proceeds via in situ formation of a highly reactive cyclopropene intermediate and subsequent diastereoselective addition of a nucleophile across the strained C═C bond. Three alternative means of controlling the diastereoselectivity of addition have been demonstrated:
Copper‐Catalyzed Enantio‐ and Diastereoselective Addition of Silicon Nucleophiles to 3,3‐Disubstituted Cyclopropenes
作者:Liangliang Zhang、Martin Oestreich
DOI:10.1002/chem.201904272
日期:2019.11.13
A highly stereocontrolled syn-addition of silicon nucleophiles across cyclopropenes with two different geminal substituents at C3 is reported. Diastereomeric ratios are excellent throughout (d.r.≥98:2) and enantiomeric excesses usually higher than 90 %, even reaching 99 %. This copper-catalyzed C-Si bond formation closes the gap of the direct synthesis of α-chiral cyclopropylsilanes.
Copper-Catalyzed Hydroamination: Enantioselective Addition of Pyrazoles to Cyclopropenes
作者:Minghao Wang、Julie C. Simon、Mengfei Xu、Stephanie A. Corio、Jennifer S. Hirschi、Vy M. Dong
DOI:10.1021/jacs.3c02971
日期:2023.7.12
Chiral N-cyclopropyl pyrazoles and structurally related heterocycles are prepared using an earth-abundant copper catalyst under mild reaction conditions with high regio-, diastereo-, and enantiocontrol. The observed N2:N1 regioselectivity favors the more hindered nitrogen of the pyrazole. Experimental and DFT studies support a unique mechanism that features a five-centered aminocupration.