Spectroscopic and Theoretical Identification of Two Thermal Isomerization Pathways for Bistable Chiral Overcrowded Alkenes
Chiroptical molecular switches play an important role in responsive materials and dynamic molecular systems. Here we present the synthesis of four chiral overcrowded alkenes and the experimental and computational study of their photochemical and thermal b
Kistemaker, Jos C. M.,Pizzolato, Stefano F.,van Leeuwen, Thomas,Pijper, Thomas C.,Feringa, Ben L.
Acid activated montmorillonite K-10 mediated intramolecular acylation: Simple and convenient synthesis of 4-chromanones
3-Aryloxyproionic acids undergo intramolecular cyclization in the presence of AA.Mont.K-10 in toluene under reflux for 30–45 min in good to excellent yields. Phenyl ring bearing various substituents at the ortho, meta, para positions undergo this cyclization reaction. This method involves simple work up and amenable for large scale preparations. The heterogeneous acid treated catalyst can be regenerated and used for up to three cycles with minimum loss of activity.
Benzyne-Mediated Nonconcerted Pathway toward Synthesis of Sterically Crowded [5]- and [7]Oxahelicenoids, Stereochemical and Theoretical Studies, and Optical Resolution of Helicenoids
Synthesis of [5]- and [7]oxahelicenoids via Diels-Alder reaction of sterically crowded bichromenes with benzyne is presented. Studies carried out on Diels-Alder addition product establish the unusual preference for a stepwise mechanism over the concerted reaction pathway. This high yielding general synthetic protocol affords unexpected anti cycloadducts [5]- and [7]oxahelicenoids, as confirmed by crystallographic analysis. To rationalize these intriguing antiaddition products, the reaction mechanism was elucidated by means of DFT analysis. Additionally, hydroxy-functionalized [7]oxahelicenoid has been resolved in its optically pure forms.
Benzyne-Mediated Nonconcerted Pathway toward Synthesis of Sterically Crowded [5]- And [7]Oxahelicenoids, Stereochemical and Theoretical Studies, and Optical Resolution of Helicenoids
Synthesis of [5]- and [7]oxahelicenoids via Diels-Alder reaction of sterically crowded bichromenes with benzyne is presented. Studies carried out on Diels-Alder addition product establish the unusual preference for a stepwise mechanism over the concerted reaction pathway. This high yielding general synthetic protocol affords unexpected anti cycloadducts [5]- and [7]oxahelicenoids, as confirmed by crystallographic analysis. To rationalize these intriguing antiaddition products, the reaction mechanism was elucidated by means of DFT analysis. Additionally, hydroxy-functionalized [7]oxahelicenoid has been resolved in its optically pure forms.
Ansa-Ruthenium(II) Complexes of R2NSO2DPEN-(CH2)n(η6-Aryl) Conjugate Ligands for Asymmetric Transfer Hydrogenation of Aryl Ketones
New 3rd generation designer ansa-ruthenium(II) complexes featuring N,C-alkylene-tethered N,N-dialkylsulfamoyl-DPEN/η6-arene ligands, exhibited good catalytic performance in the asymmetric transfer hydrogenation (ATH) of various classes of (het)aryl ketones in formic acid/triethylamine mixture. In particular, benzo-fused cyclic ketones furnished 98 to >99.9% ee using a low catalyst loading.
Ki?ic, Andrea,Stephan, Michel,Mohar, Barbara
supporting information
p. 2540 - 2546
(2015/08/18)
A Novel and Convenient Mercury(II) Mediated Synthesis of Chroman-4-ones
A simple route to chroman-4-ones from γ-bromopropynyl aryl ethers (1) using mercury(II) trifluoroacetate as a catalyst is described.
Gopalsamy, Ariamala,Balasubramanian, K. K.
p. 34 - 35
(2007/10/02)
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