Iridium Diamine Catalyst for the Asymmetric Transfer Hydrogenation of Ketones
作者:Henar Vázquez-Villa、Stefan Reber、Martin A. Ariger、Erick M. Carreira
DOI:10.1002/anie.201102732
日期:2011.9.12
A simple and very efficient chiral aqua iridium(III) diamine complex leads to excellent enantioselectivities in the asymmetrictransferhydrogenation of various α‐cyano and α‐nitro ketones. The catalyst provides the ortho‐substituted aromatic alcohols with especially high ee values. The diamine ligands can be used directly as chiral ligands; conversion into the corresponding sulfamide is not necessary
Novel Synthesis of α-Keto Esters and Amides by an sp3 C–H Oxidation of Nitromethyl Aryl Ketones Promoted by Ion-Supported (Diacetoxyiodo)benzene
作者:Yuanyuan Xie、Xiaoying Jiang、Bing Gan、Jiwei Liu
DOI:10.1055/s-0035-1562535
日期:——
A simple and efficient method is described for the preparation of α-keto esters or amides from nitromethyl aryl ketones. In the presence of nucleophiles (alcohols or amines), the ion-supported (diacetoxyiodo)benzene-promoted sp3 C–H oxidation of nitromethyl aryl ketones proceeded efficiently under mild conditions to give the corresponding α-keto esters and amides in moderate to good yields. This is the
A practicalone‐pot protocol for the synthesis of 2,5‐disubstitutedoxazoles from 1‐aryl‐2‐nitroethanones was reported. In the presence of iron/AcOH in acetonitrile, the reaction of 1‐aryl‐2‐nitroethanones with trimethyl orthoacetate or trimethyl orthobenzoate delivered the corresponding 2,5‐disubstitutedoxazoles in moderate to good yields.
Organocatalytic asymmetric Michael/hemiacetalization/acyl transfer reaction of α-nitroketones with <i>o</i>-hydroxycinnamaldehydes: synthesis of 2,4-disubstituted chromans
作者:Rajendra Maity、Subhas Chandra Pan
DOI:10.1039/c8ob00078f
日期:——
An organocatalyticasymmetriccascadeMichael/hemiketalization/acyl transfer reaction between o-hydroxycinnamaldehydes and α-nitroketones is developed. Prolinol TMS ether catalyst in combination with benzoic acid was found to be the most effective for this reaction which proceeds through an equilibrium of lactols to provide a single diastereomer of enantiopure 2,4-disubstituted chromans.
Regioselective synthesis of functionalized 4-nitro- and 4-amino-phenols based on formal [3+3] cyclocondensations of 3-ethoxy-2-nitro-2-en-1-ones with 1,3-bis(silyloxy)-1,3-butadienes
作者:Abdolmajid Riahi、Mohanad Shkoor、Rasheed Ahmad Khera、Helmut Reinke、Peter Langer
DOI:10.1016/j.tetlet.2009.03.190
日期:2009.6
Functionalized 4-nitro- and 4-aminophenols were regioselectively prepared based on [3+3] cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with 3-ethoxy-2-nitro-2-en-1-ones.