- Scalable anti-Markovnikov hydrobromination of aliphatic and aromatic olefins
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To improve access to a key synthetic intermediate we targeted a direct hydrobromination-Negishi route. Unsurprisingly, the anti-Markovnikov addition of HBr to estragole in the presence of AIBN proved successful. However, even in the absence of an added initiator, anti-Markovnikov addition was observed. Re-examination of early reports revealed that selective Markovnikov addition, often simply termed "normal" addition, is not always observed with HBr unless air is excluded, leading to the rediscovery of a reproducible and scalable initiator-free protocol.
- Galli, Marzia,Fletcher, Catherine J.,Del Pozo, Marc,Goldup, Stephen M.
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supporting information
p. 5622 - 5626
(2016/07/06)
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- Construction of chiral 2-substituted octahydroindoles from cyclic ketones and nitroolefins bearing only one α-substituent
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A dual catalytic system has been developed following the screening of a series of chiral primary amine catalysts and chiral phosphoric acid catalysts for the Michael addition of cyclic ketones to nitroolefins bearing only one α-substituent. The resulting γ-nitro ketones, which contain a substituent on the carbon connected to the nitro group, were formed in excellent yields (>80%) with high levels of stereoselectivity (up to 94:6 dr and 98% ee) when the reaction was performed in benzene at 0 °C with 10 mol% of the optimal amine/phosphoric acid combination (1:1) as a catalyst. Subsequent reduction of the nitro group followed by intramolecular reductive amination could afford optically active cis-octahydroindole analogues bearing a non-functional substituent at their 2-position.
- Han, Yong,Zheng, Bo,Peng, Yungui
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supporting information
p. 1136 - 1142
(2015/04/22)
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- 4-aminocyclohexanol deriv. substd.
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4-aminocyclohexanol compounds, processes for their preparation, pharmaceutical formulations comprising these compounds and the use of substituted 4-aminocyclohexanol compounds for the preparation of pharmaceutical formulations and for the treatment of diverse indications, including, without limitation, pain.
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Page/Page column 30
(2010/02/11)
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- Substituted 4-aminocyclohexanol compounds
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4-aminocyclohexanol compounds, processes for their preparation, pharmaceutical formulations comprising these compounds and the use of substituted 4-aminocyclohexanol compounds for the preparation of pharmaceutical formulations and for the treatment of div
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- The effect of vinyl esters on the enantioselectivity of the lipase-catalysed transesterification of alcohols
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The enantioselectivity of the lipase from Pseudomonas cepacia (PCL) in the transesterification of 2-phenyl-1-propanol 1 was studied using a series of vinyl 3-arylpropanoates as acyl donors. The most enantioselective transesterification reaction of the alcohol was attained by using vinyl 3-(p-iodophenyl)- or 3-(p-trifluoromethylphenyl)propanoates, with enantiomer ratios, E, of 116 and 138, respectively. Vinyl 3-phenylpropanoate was also effective for the resolution of 1 mediated by lipases from P. fluorescens and porcine pancreas and for the PCL-catalysed transesterification of several 2-phenyl-1-alkanols. The enantiomeric resolution of 1 was practically carried out by the first enantioselective transesterification using PCL and vinyl 3-(p-iodophenyl)propanoate to afford (R)-1 and then the enantioselective hydrolysis of the resultant ester to afford (S)-1.
- Kawasaki, Masashi,Goto, Michimasa,Kawabata, Shigeki,Kometani, Tadashi
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p. 585 - 596
(2007/10/03)
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- Bicyclic amide derivatives and their use as muscle relaxants
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Novel compounds of formula (1) together with their salts and solvates have a number of uses in medicine, in particular as central muscle relaxants.
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- Bicyclic amide derivatives and their use as muscle relaxants
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Novel compounds of formula (I) STR1 wherein R1, R2, R3 and R4 are each selected from hydrogen and fluoro and at least one and not more than two is fluoro; R5 is selected from hydrogen and C1 -C4 alkyl; R6 is selected from hydrogen, C1 -C4 ally and hydroxy; or R5 and R6 together with the ring carbon form a carbonyl group; R7 is selected from hydrogen and hydroxy, R8 and R9 are each selected from hydrogen, C1 -C4 alkyl and cyclo(C3 or C4) alkyl or together with the nitrogen form a morpholino group; and X is selected from a bond, methylene and --O-- and is always a bond or --O-- when any of R5, R6 and R7 is other than hydrogen and is always a bond when R5 and R6 together with the ring carbon form a carbonyl group; and their salts and solvates have a number of uses as central muscle relaxants. In particular, treatment of conditions associated with abnormally raised skeletal muscle tone. They are of special value in the relaxation of skeletal muscle in spastic, hypertonic and hyperkinetic conditions.
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- Reactions of Co-ordinated Ligands. Part 10. Rhodium-catalysed Cyclisation of 3-(2-Fluorophenyl)propanols to Chromans
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The cyclisation of several 3-(2-fluorophenyl)-propanols to the corresponding chroman occurs in nitromethane-acetone solution at 80 deg C when either the hexafluorophosphate (3) or tetrafluoroborate salt (4) of the (η5-ethyltetramethylcyclopentadienyl)(η6-benzene)rhodium(III) cation is used as a catalyst; the former salt is the more effective catalyst.The cyclisation is believed to involve the activation of the aryl fluoride (towards intramolecular nucleophilic substitution by the hydroxy group) by the formation of a metal complex in which the aryl fluoride is ?-bonded with the metal cation.It is suggested that the arene-exchange reaction which gives this ?-bonded complex proceeds faster with the salt (3) than with the salt (4), and that this is the main factor for the greater efficiency of the former salt as a cyclisation catalyst.
- Houghton, Roy P.,Voyle, Martyn,Price, Raymond
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p. 925 - 931
(2007/10/02)
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