An efficient organocatalytic cascade reaction has been developed involving a Michael-hemiaminalization relay for the asymmetric synthesis of spiropiperidinone derivatives bearing adjacent quaternary and tertiary chiral centers via LUMO or HOMO activation. Importantly, this methodology demonstrates that applying distinct activation modes to different substrates in the same reaction can diverge diastereoselectivity. To our knowledge, this is also one of the few published cases of primary amine catalytic [3 + 3] cycloaddition reactions involving α-branched β-ketoamides.
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http://dx.doi.org/10.1021/acs.joc.6b02489 | DOI Listing |
An N-heterocyclic carbene-catalyzed asymmetric [3 + 3] spiroannulation of β-ketothioamide was successfully developed. β-Ketothioamides exhibit an unusual reactivity to undergo a previously challenging lactamization reaction, and the desired spiro-piperidinone derivatives containing two vicinal stereogenic centers were synthesized in good to high yields with high stereoselectivities, whose structure can be converted to the corresponding imide and δ-lactam derivatives smoothly.
View Article and Find Full Text PDFMolecules
February 2017
Department of Chemistry, College of Science, King Saud University, P.O. Box 2455, Riyadh-11451, Saudi Arabia.
This article presents the synthesis of new derivatives of spirooxindole-spiropiperidinone- pyrrolidines - and spirooxindole-spiropiperidinone-pyrrolizines - through a 1,3-dipolar cycloaddition reaction of azomethineylides generated from isatin, sarcosine, and l-proline, through a decarboxylative route with dipolarophile -. All of the newly synthesized compounds were evaluated for their antimicrobial activities and their minimum inhibitory concentration (MIC) against most of the test organisms. The tested compounds displayed excellent activity against all of the tested microorganisms.
View Article and Find Full Text PDFJ Org Chem
January 2017
State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, People's Republic of China.
An efficient organocatalytic cascade reaction has been developed involving a Michael-hemiaminalization relay for the asymmetric synthesis of spiropiperidinone derivatives bearing adjacent quaternary and tertiary chiral centers via LUMO or HOMO activation. Importantly, this methodology demonstrates that applying distinct activation modes to different substrates in the same reaction can diverge diastereoselectivity. To our knowledge, this is also one of the few published cases of primary amine catalytic [3 + 3] cycloaddition reactions involving α-branched β-ketoamides.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!