A bis(amino)cyclopropenylidene (BAC) catalyzed aza-benzoin reaction between aldehydes and phosphinoyl imines has been developed. The reaction is general with a wide range of aromatic aldehydes and aromatic imines. The reaction displays excellent chemoselectivity favoring aza-benzoin products over homobenzoin products.
Nucleophile Generation via Decarboxylation: Asymmetric Construction of Contiguous Trisubstituted and Quaternary Stereocenters through a Cu(I)-Catalyzed Decarboxylative Mannich-Type Reaction
作者:Liang Yin、Motomu Kanai、Masakatsu Shibasaki
DOI:10.1021/ja9036675
日期:2009.7.22
first catalytic asymmetric decarboxylative Mannich-type reaction between aldimines and cyanocarboxylic acids was developed. Alpha,alpha,beta-trisubstituted beta-amino nitriles containing contiguous trisubstituted and all-carbon quaternary stereocenters were produced with moderate to high enantio- and diastereoselectivity using 5 mol % CuOAc-(R)-DTBM-SEGPHOS complex as an asymmetric catalyst. This reaction
The Supersilyl Group as a Carboxylic Acid Protecting Group: Application to Highly Stereoselective Aldol and Mannich Reactions
作者:Jiajing Tan、Matsujiro Akakura、Hisashi Yamamoto
DOI:10.1002/anie.201300102
日期:2013.7.8
Silyl superpowers: The supersilylgroup was investigated as a superior carboxylicacidprotectinggroup. Supersilyl esters were also utilized as stable carboxylicacid synthetic equivalents in highlystereoselectivealdol and Mannichreactions (see scheme). The value of this method lies in easy photodeprotection and in the rapid synthesis of polyketide subunits.
DirectcatalyticasymmetricMannich-typereactions of gamma-butenolides are described. A chiral Lewis acid/amine base/Bronsted acid combination was used to catalyze a gamma-addition of gamma-butenolides to N-diphenylphosphinoyl imines, affording the products in up to >99% yield, anti/syn = >97:3, and 84% ee. The use of a catalytic amount of TfOH in addition to La(OTf)3/Me-PyBox/TMEDA was important
描述了γ-丁烯内酯的直接催化不对称曼尼希型反应。手性路易斯酸/胺碱/布朗斯台德酸的组合用于催化γ-丁烯内酯向N-二苯基膦酰基亚胺的γ加成反应,从而使产物收率最高> 99%,反/ syn => 97:3,并且84%ee。除La(OTf)3 / Me-PyBox / TMEDA外,还使用催化量的TfOH对于提高收率和立体选择性很重要。
A convenient and practical method for the synthesis ofN-thiophosphoryl aldimines and ketimines
The first enantioselective addition of nitroalkanes to imines (nitro-Mannich reaction), mediated by an iron(II) catalyst assembled by a hindered hydroxyethyl-pybox ligand, is described. This valuable carbon–carbon bond-forming reaction proceeds smoothly at room temperature to afford enantioenriched β-nitro amines in good yields and high enantioselectivity, up to 98% with unprecedentedly low iron catalyst