37630-20-9Relevant articles and documents
Molecular Engineering of β-Substituted Oxoporphyrinogens for Hydrogen-Bond Donor Catalysis
Chahal, Mandeep K.,Payne, Daniel T.,Matsushita, Yoshitaka,Labuta, Jan,Ariga, Katsuhiko,Hill, Jonathan P.
supporting information, p. 82 - 90 (2020/01/02)
A new class of bifunctional hydrogen-bond donor organocatalyst using oxoporphyrinogens having increased intramolecular hydrogen-bond donor distances is reported. Oxoporphyrinogens are highly non-planar rigid macrocycles containing a multiple hydrogen bond-forming binding site. In this work, we describe the first example of non-planar OxPs as hydrogen-bond donor catalysts prepared using a molecular engineering approach of the binding site for dual activation of substrates. The introduction of β-substituents is key to the catalytic activity and the catalysts are able to catalyze 1,4-conjugate additions and sulfa-Michael additions, as well as, Henry and aza-Henry reactions at low catalyst loadings (≤ 1 mol-%) under mild conditions. Preliminary mechanistic studies have been carried out and a possible reaction mechanism has been proposed based on the bi-functional activation of both substrates through hydrogen-bonding interactions.
Asymmetric Reductive Amination of Cycloalkanones, VII: Asymmetric Synthesis of cis-1R,2R- and cis-1S,2S,-2-Arylcyclohexanamines
Nachtsheim, Corina M.,Frahm, August W.
, p. 187 - 197 (2007/10/02)
The asymmetric synthesis of cis-2-arylcyclohexanamines 4 by a three-step procedure is reported: condensation of racemic 2-arylcyclohexanones 1 with the chiral auxiliary R-(+)- or S-(-)-1-phenylethylamine, respectively, leads to a mixture of the imin isomers 2.Upon hydrogenation with Raney-Nickel just one secondary amin of type 3 is obtained, which is hydrogenolyzed to the optically active primary cis-2-arylcyclohexanamines 4.The relative configuration as well as the conformation were derived from 1H-NMR data.The absolute configuration of the highly enantiomericallypure compounds 4 was determined by CD spectra.
