Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives

• Jan Bartáček,
• Karel Chlumský,
• Jan Mrkvička,
• Lucie Paloušová,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62

• based on derivatives of imidazolidin-4-one were synthesised and characterised. The catalytic activity and enantioselectivity of their corresponding copper(II) complexes were studied in asymmetric Henry reactions. It was found that the enantioselectivity of these catalysts is overall very high and

• -(pyridin-2-yl)imidazolidin-4-one, differentiated by various substitutions at the imidazolidine ring [5][6][7]. Their copper(II) complexes were evaluated as efficient enantioselective catalysts, particularly in asymmetric Henry reactions (Scheme 1). Subsequent research has led to the development of various

• , chiral 2-(pyridin-2-yl)imidazolidin-4-one derivatives stand out as a prominent class of chiral nitrogen ligands in enantioselective catalysis. In this work, we focused on structurally modifying 2-(pyridin-2-yl)imidazolidin-4-one ligands to potentially expand the range of efficient catalysts. Our goal was

The asymmetric Henry reaction as synthetic tool for the preparation of the drugs linezolid and rivaroxaban

• Martin Vrbický,
• Karel Macek,
• Jaroslav Pochobradský,
• Jan Svoboda,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2022, 18, 438–445, doi:10.3762/bjoc.18.46

• [19]. Therefore, they represent a very useful tool for diverse asymmetric transformations, including the Henry reaction. The pilot study of the synthesis of rivaroxaban through an asymmetric Henry reaction [12] described the application of only one copper complex with a 2-(pyridin-2-yl)imidazolidin-4

• -one derivative. Here, we extended the series of catalysts to include copper complexes with another six 2-(pyridin-2-yl)imidazolidin-4-ones Ia,b–IIIa,b [20][21][22], four bisoxazolines IV–VII [23][24], and as chiral diamine, the alkaloid (+)-sparteine VIII [25] (Figure 2). All Henry reactions were

Synthesis of 1,3-cis-disubstituted sterically encumbered imidazolidinone organocatalysts

• Jan Wallbaum and
• Daniel B. Werz

Beilstein J. Org. Chem. 2017, 13, 2577–2583, doi:10.3762/bjoc.13.254

• mixture was stirred at ambient temperature for 24 h. The suspension was filtered over Celite and the solvent was removed in vacuo. (2S,5S)-5-((N-Methyl-1H-imidazol-4-yl)methyl)-3-methyl-2-(naphthalen-1-yl)imidazolidin-4-one (7b). (S)-N-Methylhistidine methyl amide (190 mg, 1.04 mmol, 1.0 equiv), 1

• , 343.1529. (2S,5S)-5-((Indol-3-yl)methyl)-3-methyl-2-(naphthalen-1-yl)imidazolidin-4-one (7c). (S)-Tryptophan methyl amide (340 mg, 1.56 mmol, 1.0 equiv), 1-naphthyl carbaldehyde (243 mg, 212 µL, 1.56 mmol, 1.0 equiv), 4 Å molecular sieves (160 mg) and Yb(OTf)3 (97.0 mg, 156 µmol, 10 mol %) in THF (8.0 mL

• , 180.3 (one aliphatic CH and one aromatic CH are missing); (c 1.0, CHCl3) −6.0°; IR (ATR) (cm−1): 3404, 3280, 1681, 1435, 1097; HRMS (ESI) m/z: calcd for C23H21N3O, 378.1577; found, 378.1578. (2S,5S)-5-((N-Benzylindol-3-yl)methyl)-3-methyl-2-(naphthalen1-yl)imidazolidin-4-one (7d). (S)-N

Multivalent polyglycerol supported imidazolidin-4-one organocatalysts for enantioselective Friedel–Crafts alkylations

• Tommaso Pecchioli,
• Manoj Kumar Muthyala,
• Rainer Haag and
• Mathias Christmann

Beilstein J. Org. Chem. 2015, 11, 730–738, doi:10.3762/bjoc.11.83

• described. A modified tyrosine-based imidazolidin-4-one was grafted to a soluble high-loading hyperbranched polyglycerol via a copper-catalyzed alkyne–azide cycloaddition (CuAAC) reaction and readily purified by dialysis. The efficiency of differently functionalized multivalent organocatalysts 4a–c was

• loss of activity due to immobilization, albeit moderate enantioselectivities were observed. Moreover, easy recovery by selective precipitation allowed the reuse of the catalyst for three cycles. Keywords: Friedel–Crafts; homogeneous catalysis; hyperbranched polyglycerol; imidazolidin-4-one

• immobilization of imidazolidin-4-one onto hyperbranched polyglycerol (hPG) and its application as multivalent organocatalyst. Results and Discussion To explore the synthetic utility of hPG in organocatalysis, we here report the synthesis and application of a series of three multivalent dendronized imidazolidin-4