Asymmetric Transfer Hydrogenation of Arylidene-Substituted Chromanones and Tetralones Catalyzed by Noyori–Ikariya Ru(II) Complexes: One-Pot Reduction of C═C and C═O bonds
作者:Guilherme S. Caleffi、Juliana de O. C. Brum、Angela T. Costa、Jorge L. O. Domingos、Paulo R. R. Costa
DOI:10.1021/acs.joc.0c02981
日期:2021.3.19
3-Arylidenechroman-4-ones and 2-arylidene-1-tetralones are hydrogenated to cis-benzylic alcohols in dr’s and er’s up to 99:1 via a C═C and C═O one-pot reduction in the presence of 2–5 mol % Noyori–Ikariya-type RuII chiral complexes and HCO2Na as a hydrogen source under asymmetric transfer hydrogenation–dynamic kinetic resolution (ATH-DKR) conditions. The oxidation of theses substrates resulted in the
melanine biosynthesis and fruits enzymatic browning pathways. Chemical inhibitors of tyrosinase could have potential applications in cosmetics, medicine and food industry. In this study, we evaluated 6-Methoxy-3,4-dihydronaphthalenone chalcone-like derivatives as potent tyrosinase inhibitors and radical scavengers. Methods: A series of ten 2-arylidene-6-methoxy-3,4-dihydronaphthalenone derivatives as tyrosinase
Hydroxy-directed hydroaluminations: A stereoselective approach to cycloalkanols from β-aryl enones
作者:Kevin Koch、Jacqueline H. Smitrovich
DOI:10.1016/0040-4039(94)88006-9
日期:1994.2
Various aryl substituted enones are reduced using lithium aluminum hydride to afford sterioselectively trans substituted alkanols. Mechanistic studies demonstrate 1,2 addition followed by hydroxy-directedhydroalumination of the conjugated styryl unit.
Anomalous Reaction of Rh<sub>2</sub>(OAc)<sub>4</sub>-Generated Transient Carbonyl Ylides: Chemoselective Synthesis of Epoxy-Bridged Tetrahydropyranone, Oxepanone, Oxocinone, and Oxoninone Ring Systems
structure analysis. The cycloaddition of carbonylylides with the compounds having both CO and CC groups was found to be chemo- and regioselective. Interestingly, an unusual ring enlargement of cycloadducts 34, 36, and 41 derived from CO group addition was observed, affording epoxyoxocin-4(5H)-one and epoxyoxonin-5(6H)-one frameworks. Examples for the tandem cyclization−cycloaddition−ring enlargement
Claisen-Schmidt, aza-Michael, cyclization via cascade strategy toward microwave promoted synthesis of imidazo[2,1-b]quinazolines
作者:Duraipandi Devi Priya、Selvaraj Mohana Roopan
DOI:10.1080/00397911.2020.1757112
日期:2020.6.17
Imidazole blended quinazolines are having a wide run of potential applications in synthetic field. In this current investigation, we reported a modern synthesis with the help of non-conventional energy. Optimization parameters have been stabilized utilizing RSM (Response Surface Method) as well as Taguchi models. The yield obtained from the proposed protocol is significantly higher compared to other routine strategies. The products were explored by implies of H-1, C-13-NMR and HR-MS investigation. Interestingly, cyclization & aromatization has been influenced by KOH in a greater extent. It is critical that the imidazo[1,2-b]quinazolines show intense fluorescence emission, significant stokes shift, and high quantum yield.