Enantioselective Cycloaddition of Styrenes with Aldimines Catalyzed by a Chiral Magnesium Potassium Binaphthyldisulfonate Cluster as a Chiral Brønsted Acid Catalyst
A chiral magnesium potassium binaphthyldisulfonate cluster, as a chiral Brønsted acid catalyst, was shown to catalyze an enantioselective cycloaddition of styrenes with aldimines for the first time. The strong Brønsted acidity of the catalyst precursors, which might dissolve drying agents and take up the leached Mg2+ and K+, serendipitously led to good enantioselectivity. Mechanistic aspects were supported
In the field of chiralBrønstedbase catalysis, a new generation of chiralcatalysts has been highly anticipated to overcome the intrinsic limitation of pronucleophiles that are applicable to the enantioselective reactions. Herein, we reveal conceptually new chiralBrønstedbasecatalysts consisting of two different organobase functionalities, one of which functions as an organosuperbase and the other
Ureidopeptide‐Based Brønsted Bases: Design, Synthesis and Application to the Catalytic Enantioselective Synthesis of β‐Amino Nitriles from (Arylsulfonyl)acetonitriles
作者:Saioa Diosdado、Rosa López、Claudio Palomo
DOI:10.1002/chem.201304877
日期:2014.5.19
preparation of β‐aminonitriles. We present a highly efficient organocatalytic methodology for the stereoselective synthesis of β‐aminonitriles, in which the key to success is the use of ureidopeptide‐basedBrønstedbase catalysts in combination with (arylsulfonyl)acetonitriles as synthetic equivalents of the acetonitrile anion. The method gives access to a variety of β‐aminonitriles with good yields
[EN] CYCLOPROPENIMINE CATALYST COMPOSITIONS AND PROCESSES<br/>[FR] COMPOSITIONS CATALYTIQUES À BASE DE CYCLOPROPÉNIMINE ET PROCÉDÉS
申请人:UNIV COLUMBIA
公开号:WO2013059118A1
公开(公告)日:2013-04-25
The present invention provides, inter alia, a cyclopropenimine Brønsted base catalyst and a cyclopropenimine scaffold for use as a Brønsted base catalyst. This cyclopropenimine has the structure (100). Methods for making such a cyclopropenimine are also provided. Further provided are processes for carrying out an organic synthetic reaction and processes for catalyzing a proton transfer reaction enantioselectively using such a cyclopropenimine Brønsted base catalyst.
A chiral organic base catalyst with halogen-bonding-donor functionality: asymmetric Mannich reactions of malononitrile with <i>N</i>-Boc aldimines and ketimines
A chiral organic basecatalyst with halogen-bonding-donor functionality has been developed. This quinidine-derived acid/basecatalyst smoothly promoted the asymmetricMannichreaction of malononitrile and various N-Boc imines with up to 98% ee. The cooperative interaction with both substrates was responsible for the high activity that allowed a reduction of the catalyst amount to 0.5 mol%.