Synthesis of cycloalkano[b]pyridines by multicomponent strategy: ring-size mediated product selectivity, substitution-induced axial chirality and influence of the 14N quadrupole-relaxation

Borohydride reduction of titled ketones 1a-1g gave diastereoisomeric mixtures of (Z)-1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-ols 2a-2g and 3a-3g in which the former ones prevailed. Only individual racemic products were obtained after borohydride reduction of (E)-1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)-prop-2-en-1-one 4 to corresponding 1-hydroxy derivative 5 and by conversion of (Z)-1-oxo derivative 1a to 1,3-diphenyl-3-(2-phenylimidazo[1,2-a]pyridin-3-yl)propan-1-one (6) with sodium hydrogenselenide. Diastereoselectivity of the borohydride reduction is discussed using the PM3 calculations of the molecules 1a, 2a, 2b, 3a, 3b, 4, 5, and 6.

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l-Prolinal Dithioacetal: A Highly Effective Organocatalyst for the Direct Nitro-Michael Addition to Selected Cyclic and Aromatic Ketones

Synthesis ◽

10.1055/s-0037-1611531 ◽

2019 ◽

Vol 51 (17) ◽

pp. 3356-3368

Author(s):

Piotr Pomarański ◽

Zbigniew Czarnocki

Keyword(s):

Michael Addition ◽

Ring Size ◽

Cyclic Ketones ◽

Asymmetric Syntheses ◽

Aromatic Ketones ◽

Ring Systems ◽

Effective Catalyst ◽

Acetophenone Derivatives ◽

Highly Effective ◽

Related Compounds

The synthesis of novel l-prolinal dithioacetal and its application as an organocatalyst for the direct Michael addition of cyclic ketones and acetophenone derivatives to trans-β-nitrostyrene and related compounds is described. The prolinal dithioacetal acts as effective catalyst in the case of cyclic ketones of different ring size, in particular five- and six-membered examples, as well as larger and smaller ring systems. High enantioselectivity and diastereoselectivity is observed for different substrates and trans-β-nitrostyrenes. Also, the first asymmetric syntheses of selected 2-methyl-4-nitro-1,3-diphenylbutan-1-one derivatives by application of the obtained organocatalyst is presented.

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Carbon Supported Hybrid Catalysts for Controlled Product Selectivity in the Hydrosilylation of Alkynes

Catalysis Science & Technology ◽

10.1039/d0cy02136a ◽

2021 ◽

Author(s):

Max Roemer ◽

Vinicius Romero Gonçales ◽

Sinead Teresa Keaveney ◽

Indrek Pernik ◽

Jiaxin Lian ◽

...

Keyword(s):

Carbon Black ◽

Product Selectivity ◽

Hybrid Catalysts

A series of Rh- and Ir-hybrid catalysts with varying tether lengths has been prepared by immobilization of RhI, RhIII and IrIII complexes on carbon black via radical grafting. The performance...

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Catalytic Asymmetric Synthesis of Silicon‐Stereogenic Dihydrodibenzosilines: Silicon‐Central to Axial Chirality Relay

Angewandte Chemie ◽

10.1002/ange.202103748 ◽

2021 ◽

Author(s):

Chuan He ◽

Yonghong Guo ◽

Meng-Meng Liu ◽

Xujiang Zhu ◽

Liru Zhu

Keyword(s):

Asymmetric Synthesis ◽

Axial Chirality ◽

Catalytic Asymmetric Synthesis ◽

Catalytic Asymmetric

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Controlling Product Selectivity with Nanoparticle Composition in Tandem Chemo-Biocatalytic Styrene Oxidation

Green Chemistry ◽

10.1039/d0gc04320f ◽

2021 ◽

Author(s):

Derik Wilbers ◽

Joseph Brehm ◽

Richard Lewis ◽

Jacqueline Van Marwijk ◽

Thomas Davies ◽

...

Keyword(s):

Heterogeneous Catalysis ◽

Product Selectivity ◽

Styrene Oxidation ◽

One Pot ◽

Potential Approach ◽

Reaction Cascades

The combination of heterogeneous catalysis and biocatalysis into one-pot reaction cascades is a potential approach to integrate enzymatic transformations into existing chemical infrastructure. Peroxygenases, which can achieve clean C-H activation,...

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