60206-81-7Relevant academic research and scientific papers
Ir/f-Ampha complex catalyzed asymmetric sequential hydrogenation of enones: a general access to chiral alcohols with two contiguous chiral centers
He, Lin,Li, Ruihao,Li, Wendian,Long, Jiao,Lv, Hui,Song, Nan,Yang, Tilong,Zhang, Xumu
, p. 1808 - 1814 (2022/02/21)
A general and highly efficient method for asymmetric sequential hydrogenation of α,β-unsaturated ketones has been developed by using an iridium/f-Ampha complex as the catalyst, furnishing corresponding chiral alcohols with two contiguous stereocenters in high yields with excellent diastereo- and enantioselectivities (up to 99% yield, >20?:?1 dr and >99% ee). Control experiments indicated that the CC and CO bonds of the enones were hydrogenated sequentially, and the final stereoselectivities were determined by the dynamic kinetic resolution of ketones. Moreover, DFT calculations revealed that an outer sphere pathway was involved in both reduction of CC and CO bonds of enones. The synthetic utility of this method was demonstrated by a gram-scale reaction with very low catalyst loading (S/C = 20?000) and a concise synthetic route to key chiral intermediates of the antiasthmatic drug CP-199,330. This journal is
Rhodium-Catalyzed Asymmetric Transfer Hydrogenation/Dynamic Kinetic Resolution of 3-Benzylidene-Chromanones
Molina Betancourt, Ricardo,Phansavath, Phannarath,Ratovelomanana-Vidal, Virginie
, p. 1621 - 1625 (2021/03/08)
Straightforward access to enantiomerically enriched cis-3-benzyl-chromanols from (E)-3-benzylidene-chromanones was developed through Rh-catalyzed asymmetric transfer hydrogenation. This transformation allowed the reduction of both the CaC and CaO bonds and the formation of two stereocenters in high yields with excellent levels of diastereo- A nd enantioselectivities (up to >99:1 dr, up to >99% ee) in a single step through a dynamic kinetic resolution process using a low catalyst loading and HCO2H/DABCO as the hydrogen source.
Synthesis and antirhinovirus activity of new 3-benzyl chromene and chroman derivatives
Conti, Cinzia,Desideri, Nicoletta
experimental part, p. 3720 - 3727 (2009/10/02)
A series of 3-benzyl chromenes and chromans were synthesized and tested in vitro against human rhinovirus (HRV) 1B and 14, two representative serotypes for rhinovirus group B and A, respectively. All the new compounds, with the exception of 3-benzyl-2H-chromene (3a), showed a potent activity against HRV serotype 1B within micro or submicromolar range (IC50s from 0.11 to 6.62 μM). The low cytotoxicity of all the derivatives resulted in compounds with high therapeutic index (TI). On the contrary, HRV 14 infection was only weakly inhibited by the majority of these compounds. The 3-benzylidenechromans 2b and 2c showed the highest anti-HRV 1B activity (IC50 0.12 and 0.11 μM, respectively) coupled with remarkable TI (625.00 and 340.91, respectively). Mechanism of action studies on (Z)-3-(4-chlorobenzylidene)chroman (2b) suggest that the new compounds behave as capsid binders and interfere with very early stages of HRV 1B replication, similarly to related flavanoids.
Tributyltin hydride-mediated radical cyclisation of carbonyls to form functionalised oxygen and nitrogen heterocycles
Bentley, Jon,Nilsson, Paul A.,Parsons, Andrew F.
, p. 1461 - 1469 (2007/10/03)
The tributyltin hydride-mediated cyclisation of unsaturated ethers and amines bearing an aldehyde or α,β-unsaturated ketone group is reported. Cyclisation proceeds via reversible addition of the tributyltin radical to the carbonyl double bond to form an intermediate O-stannyl ketyl. This nucleophilic radical can add intramolecularly to electron-rich double bonds to form substituted 5- or 6-membered rings. The efficiency of the cyclisation to form, for example, hydroxytetrahydrofurans, chromanols or quinolones, is shown to depend on the nature of the acceptor double bond and also on the stability of the intermediate O-stannyl ketyl. Thus, resonance-stabilised allylic or benzylic O-stannyl ketyl radicals have been shown, for the first time, to have a particular application in slow radical cyclisations leading to butyrolactones or pyrans.
Preparation of polycyclic systems by sequential 5-exo-digonal radical cyclization, 1,5-hydrogen transfer from silicon, and 5-endo-trigonal cyclization
Clive,Yang,Macdonald,Wang,Cantin
, p. 1966 - 1983 (2007/10/03)
Radicals of type 1 undergo 5-exo diagonal cyclization, and the resulting vinyl radical abstracts hydrogen from silicon to afford a silicon-centered radical. This radical closes in a 5-endo trigonal manner to generate radicals of type 4, which are reduced
Tributyltin hydride-mediated radical cyclisation of aldehydes and unsaturated ketones: The synthesis of hydroxy tetrahydrofurans, chromanols and related compounds
Bebbington, David,Bentley, Jon,Nilsson, Paul A.,Parsons, Andrew F.
, p. 8941 - 8945 (2007/10/03)
The tributyltin hydride-mediated cyclisation of unsaturated ethers bearing an aldehyde or α,β-unsaturated ketone group is reported. Cyclisation proceeds via addition of the tributyltin radical to the carbonyl double bond and the resultant O-stannyl ketyl can add intramolecularly to electron-rich double bonds to form hydroxy tetrahydrofurans, chromanols or related compounds. (C) 2000 Elsevier Science Ltd.
Preparation of tetrahydrofuran, γ-lactone, chromanol and pyrrolidine systems by sequential 5-exo-digonal radical cyclization, 1,5-hydrogen transfer from silicon, and 5-endo-trigonal cyclization
Clive, Derrick L. J.,Yang, Wen
, p. 1605 - 1606 (2007/10/03)
Sequential 5-exo-digonal radical closure, intramolecular 1,5-hydrogen transfer from silicon to carbon, and 5-endo-trigonal closure of the resulting silicon-centred radicals are used to make five- and six-membered heterocycles containing oxygen or nitrogen.
Reductions by hydrides and hydroboration. The stereoselectivity of new access methods to 3-arylmethyl-4-chromanones (homoisoflavone derivatives)
Gomis,Kirkiacharian
, p. 1849 - 1858 (2007/10/02)
The reduction of 3-arylmethyl-4-chromanones by sodium borohydride, lithium tri-tert-butoxyaluminum hydride and hydroboration followed by oxydation of 3-benzyl-4-hydroxy-coumarines lead to mixtures of Cis and Trans diastereoisomers of 3-arylmethyl-4-chroma
Reduction par les hydrures : synthese et stereochimie des benzyl-3 chromannols-4
Gomis, M.,Kirkiacharian, B.S.,Likforman, J.,Mahuteau, J.
, p. 585 - 590 (2007/10/02)
Reduction of 3-arylidene 4-chromannones with lithium aluminium hydride leads in straightforward fashion to two 3-arylmethyl 4-chromannols diastereoisomers, for each derivative.Stereochemistry of 3-benzyl 4-chromanols is resolved by 1H and 13C NMR.Major trans compounds were obtained.
Stereospecificity of Introduction of Hydride Ion during Double Bond Reduction of 2-Benzylidene-1-tetralone and Other Related Compounds
Chatterjee, Amareshwar,Dutta, Lakshmi N.,Chatterjee, Swapan K.
, p. 955 - 960 (2007/10/02)
Lithium aluminium hydride reduction of the benzylidene derivatives (1a-c) and (5) in refluxing THF is shown to be stereospecific, the saturated alcohol isolated in each case having the trans-stereochemistry.The benzyl ketones (30a, b, d) and (7) on sodium
