ABSTRACT
Ironing out the details: Proline and pyrrolidine derivatives (Hayashi- Jørgensen catalysts) are considered "work horses" in organocatalysis. This report describes a new effective ferrocenyl pyrrolidine catalyst that is able to perform well in benchmark organocatalytic reactions (see figure). The ferrocene moiety controls the conformational space and a simple alkyl group effectively covers a face of the derived enamine. This new framework can find applications in organocatalysis, and in general, in new ligand design.
Subject(s)
Amines/chemistry , Ferrous Compounds/chemical synthesis , Proline/analogs & derivatives , Pyrrolidines/chemical synthesis , Catalysis , Ferrous Compounds/chemistry , Molecular Structure , Proline/chemical synthesis , Proline/chemistry , Pyrrolidines/chemistry , StereoisomerismABSTRACT
We herein present a general enamine-mediated α-alkylation of α-substituted aldehydes with carbenium ions for the stereoselective construction of quaternary stereogenic centers.
ABSTRACT
In this report, we have presented the first diastereoselective addition of phenylacetylene to chiral racemic chloroketones. The addition is controlled by the reactivity of the chloroketones that allowed the stereoselective reaction to be performed at -20 °C. Chiral racemic chloroketones are used in the reaction. By carefully controlling the temperature and the reaction time we were able to isolate the corresponding products in moderate yields and with good, simple and predictable facial stereoselection. Our reaction is a rare example of the use of chiral ketones in an enantioselective alkynylation reaction and opens new perspectives for the formation of chiral quaternary stereocenters.
Subject(s)
Acetylene/analogs & derivatives , Ketones/chemistry , Acetylene/chemistry , Catalysis , Ligands , Nuclear Magnetic Resonance, Biomolecular , Organic Chemistry Phenomena , StereoisomerismABSTRACT
N,N'-bis-((8-hydroxy-7-quinolinyl)methyl)-1,10-diaza-18-crown-6 ether 1a and its analogue 1c are known as fluorescent sensors of magnesium in living cells. With the aim to investigate the effects of the substitution pattern on the photophysical properties of ligands 1 and their metal complexes, we developed an efficient microwaves enhanced one-pot Mannich reaction to double-armed diaza-crown ligands 1 carrying a variety of substituents. This new protocol is characterized by shorter reaction times, enhanced yields, and improved product purities with respect to the use of conventional conductive heating.
