Asymmetric Catalysis with Silicon-Based Cuprates: Enantio- and Regioselective Allylic Substitution of Linear Precursors
作者:Alexander Hensel、Martin Oestreich
DOI:10.1002/chem.201501371
日期:2015.6.15
linear allylic phosphates that makes use of catalytically generated cuprate‐type siliconnucleophiles is reported. The method relies on soft bis(triorganosilyl) zincs as silicon pronucleophiles that are prepared in situ from the corresponding hard lithium reagents by transmetalation with ZnCl2. With a preformed chiral N‐heterocyclic carbene–copper(I) complex as catalyst, exceedingly high enantiomeric excesses
Copper-Catalyzed Perfluoroalkylation of Allyl Phosphates with Stable Perfluoroalkylzinc Reagents
作者:Lihua Liu、Xifei Bao、Hua Xiao、Junlan Li、Feifan Ye、Chaoqin Wang、Qinhua Cai、Shilu Fan
DOI:10.1021/acs.joc.8b02432
日期:2019.1.4
copper-catalyzed cross-coupling of allyl phosphates with stable perfluoroalkylzinc reagents has been developed. The reaction proceeds under mild reaction conditions with high efficiency, good functional group tolerance, and high regio- and stereoselectivities and provides general, straightforward, and useful access to allyl-perfluoroalkyl compounds. Preliminary mechanistic studies reveal that the allyl
Asymmetric Synthesis of α-Chiral Allylic Silanes by Enantioconvergent γ-Selective Copper(I)-Catalyzed Allylic Silylation
作者:Lukas B. Delvos、Devendra J. Vyas、Martin Oestreich
DOI:10.1002/anie.201300648
日期:2013.4.22
way: Regio‐ and enantioselective allylic substitution with a silicon nucleophile generated by copper(I)‐catalyzed SiB bond activation provides direct access to α‐chiral allylicsilanes from linear acceptors. The enantioconvergent catalysis employing McQuade's six‐membered N‐heterocyclic‐carbene–copper(I) catalyst is applicable to aryl‐ and alkyl‐substituted allylic phosphates (see scheme).
A potassium‐bis(trimethylsilyl)amide‐mediated cyclopropanation of allylphosphates with silylboronates has been developed. Unlike the reported copper‐catalyzed allylic substitution reactions, the nucleophile selectively attacks at the β‐position of the allylic substrates under the present reaction conditions. The mechanism of this process has also been investigated, thus indicating the involvement
A Pd(OAc)2/P(OPh)3 combination catalyzed Tsuji–Trost-type allylic amination under aerobic conditions. Both aromatic and aliphatic secondary amines were transformed into the corresponding allylic amines with a tiny amount of the catalyst system (typically 0.02 mol % Pd), only when allylic phosphates were employed as electrophiles. Other typical electrophiles, such as allylic acetate and carbonate, were