Silver-catalyzed cascade reaction of o-aminoaryl compounds with alkynes: an aniline mediated synthesis of 2-substituted quinolines

An efficient silver-catalyzed, aniline mediated cascade hydroamination/cycloaddition of o-aminoaryl compounds including o-aminoaryl aldehydes, o-aminoaryl ketones with alkynes for the synthesis of 2- or 2,4-substituted quinolines is reported. The reactions proceed with high regioselectivity to afford mono- or disubstituted quinoline derivatives in good to high yields using AgOTf as the catalyst in the air.     

Enantioselective synthesis of fused dihydropyranones via squaramide-catalyzed Michael addition/lactonization cascade reaction

A highly enantioselective (49–99% ee) Michael addition/lactonization cascade process has been developed to construct 3,4-dihydropyran-2-one in the presence of a bifunctional squaramide. Various α,β-unsaturated N-acyl heterocycles were well tolerated and afforded 3,4-dihydropyran-2-ones in moderate to excellent isolated yields (50–99%). Both cyclic and acyclic β-diketones functioned as appropriate donors. The resulting 3,4-dihydropyran-2-ones could be readily converted into oxadecalinones.     

Iron-catalyzed Michael reactions revisited: a synthetically useful process for the preparation of tri-carbonyl compounds and chiral warfarin

The LBAs (Lewis acid-assisted Brønsted acid catalysis) is proposed as possible mechanistic process in the simple FeCl₃-catalyzed Michael reactions of chalcones with active methylene compounds in organic solvents. And iron salts were found to be effective promoters in the asymmetric Michael addition of 4-hydroxycoumarin to α,β-unsaturated ketone, which resulted in excellent yield and high level of enantioselectivity (up to 91% ee) in the presence of low catalytic amount of iron and simple chiral primary amine.     

Lewis acid-catalyzed Friedel-Crafts/Michael cascade reaction of N,N-dialkyl-3-vinylanilines with N-tosylaziridines for the stereoselective synthesis of highly functionalized tetrahydroisoquinolines

A Lewis acid-catalyzed Friedel-Crafts/Michael cascade reaction between N-dialkyl-3-vinylanilines and N-tosylaziridines has been developed for the stereoselective synthesis of tetrahydroisoquinolines (THIQs). The reaction using Gd(OTf)₃ as the Lewis acid catalyst was tolerant to the various N-dialkyl-3-vinylaniline and N-tosylaziridine substrates and provided access to 28 new, highly functionalized THIQs in typically high yields with moderate- to- excellent diastereoselectivities.     

有机催化不对称Michael/环化串联反应的研究进展北大核心CSCD

串联反应能够减少反应步骤、简化操作、降低成本、实现高效率转化,符合原子经济性和绿色化学理念.特别是有机催化的不对称串联环化反应以一锅法连续催化多个化学反应,为高效合成多手性中心环状结构提供了新方法.不对称Michael/环化串联反应是构建光学活性状化合物的常用方法之一,近些年,各种有机小分子催化剂应用于不对称Michael/环化串联反应的报道不断增加,并且取得了重大进展.我们根据不同的催化剂类型综述了近5年来关于不对称Michael/环化串联反应的研究进展,并对有机催化不对称Michael/环化串联反应的发展趋势进行了展望.     

Organocatalytic asymmetric cascade cyclization reaction of o-hydroxy cinnamaldehydes with diphenylphosphine oxide

A highly stereoselective asymmetric cascade cyclization reaction between o-hydroxycinnamaldehydes and diphenylphosphine oxide has been achieved with 84%-99% ee and 7:1-20:1 dr under the catalysis of L-prolinol silyl ether.     

Highly stereoselective Michael reduction/intramolecular Michael reaction cascade to synthesize trans-stereodiad comprising an all-carbon quaternary stereogenic center

A highly stereoselective Michael reduction/intramolecular Michael reaction cascade is described. The cascade is initiated by the regioselective Michael reduction of an α-methylidene ester with L-Selectride. This is followed by the highly stereoselective intramolecular Michael reaction which efficiently constructs a six-membered carbocyclic ring with formation of the trans-stereodiad, composed of an all-carbon quaternary center and a tertiary stereogenic center. The stereoselectivity is perfectly controlled by the choice of alkene geometry in the Michael acceptor.     

One-pot synthesis of 3-(sulfonyl)-5,6,7,8-tetrahydro-4H-pyrano[3,2-c]pyridines through a cascade Michael/cyclization reaction

In this paper, a straightforward and valid three-component Michael/cyclization reaction of (E)-1-methyl-3-(arylidene)piperidin-4-ones, 2-(sulfonyl)acetonitriles, and aromatic aldehydes was explored for the preparation of potentially biologically active 3-(sulfonyl)-5,6,7,8-tetrahydro-4H-pyrano[3,2-c]pyridines under mild reaction conditions. More diverse 3-(sulfonyl)-5,6,7,8-tetrahydro-4H-pyrano[3,2-c]pyridine derivatives were constructed in satisfactory yields (up to 97%). The chemical structure of newly synthesized 3-(sulfonyl)-5,6,7,8-tetrahydro-4H-pyrano[3,2-c]pyridines were identified with ¹H-NMR, ¹³C-NMR, and mass spectrometry analysis. The recommendable method features a simple and direct workup, easy access to initial materials, high atom utilization efficiency, high final product yields, and a wide range of substrate adaptability.     

Total synthesis of (+)-UCS1025A based on a sequential Michael-retro Michael strategy featuring one-pot six-step cascade reaction

The asymmetric total synthesis of UCS1025A is accomplished by establishing a novel and efficient method for the construction of a tricyclic pyrrolizidinone skeleton based on a sequential Michael-retro Michael strategy. The key step is a one-pot six-step cascade reaction including oxidation of a primary alcohol to the corresponding carboxylic acid, a retro thio-Michael reaction, and an intramolecular oxy-Michael reaction. This newly-developed synthetic strategy inspired by “masked” electrophilic character of tricyclic pyrrolizidinone is efficient and high-yielding compared to that developed in previously-reported total syntheses.     

A novel solid state Michael addition reaction of N-heterocyclic compounds containing active C-H bond

In this paper,a novel solid state Michael-type addition reaction of N-heterocyclic compounds containing the active-CH group was investigated.3-Methyl-l-phenyl-5-pyrazolone (MPP) and indole (In) reacted with 4-arylmethylene-3-methyl-l-phenyl-5-pyrazolone (1) hi the solid state at room temperature to give the corresponding adducts,aryl-4,4'-bis(5-hydroxy-3-methyl-l-phenyl-pyrazolyl) methane (2a-n) and l-aryl-l-(5'-hydroxy-3'-methyl-1'-phenyl-4'-pyrazolyl)-l-(3"-indolyl) methane (3a-n),respectively.This is a feasible method for preparing the compound which contains two heterocyclic groups on the same carbon.     

Asymmetric Michael Addition/Intramolecular Cyclization Catalyzed by Bifunctional Tertiary Amine–Squaramides: Construction of Chiral 2‐Amino‐4H‐chromene‐3‐Carbonitrile Derivatives

The efficient asymmetric Michael addition/intramolecular cyclization of malononitrile with dienones catalyzed by a chiral bifunctional tertiary amine–squaramide catalyst for the synthesis of chiral 2‐amino‐4H‐chromene‐3‐carbonitrile derivatives was developed. The corresponding products were obtained in good to excellent yields (up to 99 %) with excellent enantioselectivities (up to 98 % ee) for most of the bisarylidenecyclopentanones.     

Acylzirconocene chloride: Formation of carbocycles by palladium-catalyzed cascade reaction

Acylzirconocene chloride complex as an acyl group donor reacts with ω-carbonyl α,β-enones or with bis-enones to give carbocyclic compounds under 10 mol% Pd(OAc)₂-catalyzed conditions, and each reaction was accelerated by the addition of a stoichiometric amount of Me₂Zn. The formation of the carbocycles from ω-carbonyl α,β-enones was considered to be a result of a series of reactions; (i) the formation of Pd(II)-intermediate by an electron transfer from the Pd(0)-catalyst to an α,β-enone function in an initial step, (ii) an acyl group transfer from the acylzirconocene complex to the Pd(II)-intermediate (transmetalation), (iii) the reductive elimination of Pd(0)-metal, and (iv) an intramolecular addition of metal enolate to ω-carbonyl group. On the other hand, the reaction of bis-enones with acylzirconocene chloride under the identical condition afforded reductive cyclization product, bicyclo[3.3.0] octane derivatives, in which acyl group from acylzirconocene complex was not incorporated.     

Synthesis of poly-substituted pyrazolo[1,5-a]quinolines through one-pot two component cascade reaction

A diversity-oriented method for the synthesis of novel poly-substituted pyrazolo[1,5-a]quinolines has been developed on the basis of an S_NAr/Knoevenagel cyclization cascade reaction or an S_NAr/Dieckmann–Thorpe cyclization cascade reaction. The methods provide a variety of poly-substituted pyrazolo[1,5-a]quinolines bearing an amino, alkyl or aryl substituent at the 5-position. In addition, a diversity-oriented method for the synthesis of 2-substituted pyrazolo[1,5-a]quinolines from a readily available 2-[[(trifluoromethyl)sulfonyl]oxy]pyrazolo[1,5-a]quinoline has also been disclosed.     

Uncatalyzed Michael addition of indoles: synthesis of some novel 3-alkylated indoles via a three-component reaction in solvent-free conditions

Synthesis of some novel 3-alkylated indoles via an uncatalyzed Michael addition of indoles using three components in one-pot solvent-free conditions is reported. The mechanism was established by performing the reaction in two steps. The reaction was also studied in different solvents and an important solvent effect was noticed.     

冬凌草甲素和冬凌草乙素与谷胱苷肽的迈克尔加成反应

采用紫外光谱动力学方法测定了抗肿瘤对映贝壳杉烯二萜冬凌草甲素和冬凌草乙素与谷胱苷肽迈克尔加成反应的级数、速率常数和平衡常数.结果表明,冬凌草甲素和冬凌草乙素与与谷胱苷肽迈克尔加成反应符合二级动力学方程,25℃下的速率常数分别为16.196 0L·(mol·s)-1和7.480 5L·(mol·s)-1,平衡常数分别为177.98L/mol和85.60L/mol.冬凌草甲素与谷胱苷肽迈克尔加成反应速率和反应程度均比冬凌草乙素的大得多,反应活性更好.对映贝壳杉烯二萜通过与机体发生迈克尔加成反应而产生抗肿瘤作用;因此,冬凌草甲素可能比冬凌草乙素具有更好的抗肿瘤活性.