Remarkable generality in scope of DATs/Cu catalysts for enantioselective nitroaldolreaction is described; excellent levels of stereoinduction are recorded for a range of aldehydes (ee 81-99%, 17 examples) and the possibility to employ the present catalytic system as the key step for the preparation of highly functionalized tetrahydro-isoquinolines is demonstrated.
alcohol–CuII catalyst: Highlyenantioselective Henry reactions between aromatic aldehydes and nitromethane have been developed. The reactions were catalyzed by an easily available and operationally simple amino alcohol–copper(II) catalyst (see scheme). In total, 38 substrates were tested and the R‐configured products were obtained in good yields with excellent enantioselectivities.
氨基醇-Cu II 催化剂:已开发出芳香醛与硝基甲烷之间的高度对映选择性的亨利反应。反应是由易于获得且操作简单的氨基醇-铜(II)催化剂催化的(请参见方案)。总共测试了38种底物,并以高收率和出色的对映选择性获得了R构型的产品。
Trifunctional Squaramide Catalyst for Efficient Enantioselective Henry Reaction Activation
作者:Juan V. Alegre-Requena、Eugenia Marqués-López、Raquel P. Herrera
DOI:10.1002/adsc.201600046
日期:2016.6.2
means of multiple interactions has been found in a study of the Henry reaction. Enantiomerically enriched nitroaldol products were obtained in good yields and high enantioselectivitiesunder mild conditions using one of the smallest amounts of organocatalyst reported so far for this reaction (0.25 mol%). The catalyst was able to generate hydrogen bonding and anion‐π/hydrogen‐πinteractions with the substrates
A new poly(ethylene glycol)-modified DAT2-Cu(OAc)(2) complex smoothly catalyzes a base-free nitroaldol condensation in a highly enantioselective manner (ee up to 93%) also in reagent-grade solvent and in the presence of air. Effective recovery and recycling (up to five runs) of supported catalysts are documented.