نتایج جستجو برای: intramolecular michael addition

تعداد نتایج: 747019  

Journal: :Chemical communications 2005
Stefan Sommer Herbert Waldmann

A spiro[5.5]ketal library embodying the core structure of numerous biologically active natural products was synthesized employing a double intramolecular hetero Michael reaction as a key transformation.

Journal: :Chemical communications 2015
Vasudeva Rao Gandi Yixin Lu

The first phosphine catalysed Michael addition of arylcyanoacetates to allenoates has been developed, and the β-selective products with a quaternary center were obtained in excellent yields. This unusual regioselectivity may open new opportunities to access interesting molecular structures.

Journal: :European Journal of Organic Chemistry 2021

Here we describe a direct access to 2,2,3-trisubstituted syn γ-nitroaldehydes by addition of α-branched aryl acetaldehydes nitroolefins promoted cinchona based squaric acid-derived amino acid peptide. Different α-methyl arylacetaldehydes react with β-aromatic and β-alkyl afford the Michael adducts in high enantioselectivity syn-selectivity. NMR experiments DFT calculations predict reaction occu...

Journal: : 2021

Pyrazolines, which are nitrogen including five-membered heterocyclic structures, have been used in the organic and pharmaceutical industries. This study aimed was to synthesize characterizes new series of 3,5-diphenyl-4,5-dihydro-1H-pyrazole derivatives. The pyrazoline compounds synthesized from chalcones hydrazine hydrate two steps. In first step, were 2-amino acetophenone various substituted ...

Journal: :Organic & biomolecular chemistry 2011
Qiang Kang Yugen Zhang

Aza-Michael addition of amines, including aromatic and aliphatic amines, with α, β-unsaturated ketones was realized employing N-Heterocyclic Carbene (NHC) as organocatalyst, yielding β-amino ketones with up to 98% yield.

Journal: :Organic & biomolecular chemistry 2011
Wenjun Li Wenbin Wu Feng Yu Huicai Huang Xinmiao Liang Jinxing Ye

Catalytic asymmetric Michael additions with curcumin derivatives were achieved by a new series of tertiary amine-thiourea organocatalysts to afford the Michael adducts in high yields and excellent enantioselectivities.

Journal: :Bulletin of the Chemical Society of Japan 1987

Journal: :Organic & biomolecular chemistry 2013
Yu-Ting Lee Yen-Te Lee Chia-Jui Lee Chia-Ning Sheu Bo-Yu Lin Jeng-Han Wang Wenwei Lin

An efficient synthesis of tetrasubstituted furans was achieved from the corresponding α,β-unsaturated ketone derivatives, acid chlorides, and Bu3P in the presence of Et3N via a chemoselective intramolecular Wittig reaction as the key step. The presence of an additional electron-withdrawing group in the α-position of Michael acceptors controlled the chemoselectivities of presumable phosphorus yl...

Journal: :Chemical communications 2009
Yi Li Xue-Qiang Wang Chao Zheng Shu-Li You

Camphor-derived chiral triazolium salts have been found to be highly efficient for asymmetric intramolecular Michael reactions. With 1-5 mol% of the catalyst, the desired products were obtained in excellent yields, with up to 99% ee.

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