Organocatalytic asymmetric desymmetrization: efficient construction of spirocyclic oxindoles bearing a unique all-carbon quaternary stereogenic center via sulfa-Michael addition

2013 ◽  
Vol 49 (54) ◽  
pp. 6078 ◽  
Author(s):  
Lu Yao ◽  
Kang Liu ◽  
Hai-Yan Tao ◽  
Guo-Fu Qiu ◽  
Xiang Zhou ◽  
...  
Keyword(s):  
Michael Addition ◽  
Efficient Construction ◽  
Stereogenic Center

Thiosquaramide-catalysed asymmetric double Michael addition of 2-(3H)-furanones to nitroolefines

2019 ◽  
Vol 17 (11) ◽  
pp. 2883-2886 ◽  
Author(s):  
Mengchen Yang ◽  
Chen Chen ◽  
Xing Yi ◽  
Yuan Li ◽  
Xiaoqin Wu ◽  
...  
Keyword(s):  
Michael Addition ◽  
Mild Conditions ◽  
Stereogenic Center

2,2,4-Trisubstituted butenolides bearing a quaternary stereogenic center were smoothly constructed with excellent stereoselectivities under mild conditions.

NHC-catalyzed oxidative cyclization reaction for the synthesis of 3-substituted phthalides

2014 ◽  
Vol 12 (15) ◽  
pp. 2388-2393 ◽  
Author(s):  
So Won Youn ◽  
Hyoung Sub Song ◽  
Jong Hyub Park
Keyword(s):  
Michael Addition ◽  
Functional Group ◽  
Addition Reaction ◽  
Oxidative Cyclization ◽  
Cyclization Reaction ◽  
Michael Addition Reaction ◽  
Stereogenic Center

An efficient NHC-catalyzed domino oxidation/oxa-Michael addition reaction of 2-alkenylbenzaldehydes has been developed to afford 3-substituted phthalides bearing a C3-stereogenic center with a broad substrate scope and wide functional group tolerance.

The Thomson Synthesis of (–)-GB17

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Michael Addition ◽  
Physiological Activity ◽  
Addition Product ◽  
Systematic Investigation ◽  
Unsaturated Ester ◽  
Wide Range ◽  
Stereogenic Centers ◽  
Northwestern University ◽  
Convergent Assembly ◽  
Stereogenic Center

(–)-GB17 3 is one of the Galbulimima alkaloids, a family that shows a wide range of interesting physiological activity. Regan J. Thomson of Northwestern University devised (Angew. Chem. Int. Ed. 2012, 51, 2481) a convergent assembly of 3, a key step of which was the intramolecular Michael cyclization of 1 to 2. The hydroxy aldehyde 6 was prepared by alkylation of the dithiane 4 with 5, followed by hydrolysis. The preparation of 9, by condensation of 8 with 7 followed by hydrogenation and protection, had been reported by Lhommet. Condensation of 9 with the linchpin reagent 10 gave an intermediate keto phosphonate, which was combined with 6 to give, after oxidation, the aldehyde 1. Two new stereogenic centers are created in the course of the cyclization of 1. The authors found that the TFA salt 11 of the Hayashi catalyst delivered 2 with high diastereocontrol. Control experiments showed that the buttressing effect of the dithiane was required for the cyclization. The authors then explored the next intramolecular Michael cyclization of 13 to 14. In this cyclization, the stereogenic center at 6 is in jeopardy by elimination and readdition. Cyclization of the trans unsaturated ester led to the wrong diastereomer of 14, but cyclization of the cis ester 13, prepared by the Still-Gennari protocol, cleanly gave the desired diastereomer. The reaction worked best with the free amine. Under the conditions of the reaction the Michael addition product spontaneously cyclized to the lactam 14. The ketone of 14 was selectively enolized, then converted to its enol triflate, which under Pd-mediated reduction gave the alkene 15. Alkylation of 15 with 16 predominantly gave the diene 18. Hydrolysis of the dithiane to the ketone followed by reduction gave mainly the desired equatorial alcohol, which was cleaved oxidatively to (–)-GB17 3. Although there have been many isolated reports of the utility of intramolecular Michael addition as a synthetic method, there has been little systematic investigation. The optimization studies that are the heart of this work are a welcome addition.

Bifunctional squaramides with benzyl-like fragments: analysis of CH···π interactions by Multivariate Linear Regression model and Quantum Chemical Topology

2021 ◽  
Author(s):  
Howard Díaz-Salazar ◽  
Eddy Ivanhoe Jiménez ◽  
Wilmer Esteban Vallejo Narváez ◽  
Tomás Rocha-Rinza ◽  
Marcos Hernández-Rodríguez
Keyword(s):  
Linear Regression ◽  
Regression Model ◽  
Michael Addition ◽  
Linear Regression Model ◽  
Quantum Chemical ◽  
Multivariate Linear Regression Model ◽  
Π Interactions ◽  
Chemical Topology ◽  
Quantum Chemical Topology ◽  
Stereogenic Center

We analyzed 15 bifunctional squaramides with benzyl-like fragments in a Michael addition. These substituents are susceptible to form CH⋯π interactions and have distinct properties: electronic features, stereogenic center, as well...

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