- Ruthenium-Catalyzed Enantioselective Hydrogenation/Lactonization of 2-Acylarylcarboxylates: Direct Access to Chiral 3-Substituted Phthalides
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Highly enantioselective tandem hydrogenation/lactonization of various 2-acylarylcarboxylates including 2-aroylarylcarboxylates were realized by using [RuCl(benzene)(S)-SunPhos]Cl as the catalyst under mild reaction conditions. Excellent enantioselectivities (up to 99.6 % ee) and activities (S/C=1000) were obtained. This convenient and practical method enables a direct access to a series of highly optically pure 3-substituted phthalides that are very important molecules as valuable pharmacological compounds and diversified synthons for medicinal chemistry. Moreover, a gram-scale reaction was performed to further demonstrate the practicality of this approach.
- Lu, Bin,Zhao, Mengmeng,Ding, Guangni,Xie, Xiaomin,Jiang, Lili,Ratovelomanana-Vidal, Virginie,Zhang, Zhaoguo
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p. 3989 - 3996
(2017/09/13)
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- Preparation and cycloaddition reactions of novel heterocyclic mesomeric betaines
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The heterocyclic mesomeric betaines 6a-c reacted with dimethyl acetylenedicarboxylate and ethyl propiolate giving the 1,3-dipolar cycloaddition products 7a-c and 8a-c, respectively. With esters of maleic, fumaric, acrylic and methacrylic acids, mesomeric betaines 6a and 6b gave substituted tetralone derivatives. (C) 2000 Elsevier Science Ltd.
- Morgan, David O.,David Ollis,Stanforth, Stephen P.
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p. 5523 - 5534
(2007/10/03)
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- Reactions of Carbonyl Compounds in Basic Solutions. Part 10. Methoxide-catalysed Cyclization of Methyl 2-Acylbenzoates and 8-Acyl-1-naphthoates
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The detailed mechanism of the methoxide-catalysed rearrangement of both normal and pseudo methyl o-acylbenzoates and 8-acyl-1-naphthoates to form indane-1,3-diones and phenalene-1,3-diones, respectively, has been studied.Rate-acidity function correlations for the reactions in methanolic dimethyl sulphoxide give linear relations.The kinetic isotope effect has been observed with kH/kD equal to 0.7-0.9 and 5-7 for methyl o-acetylbenzoate and normal methyl 8-acetyl-1-naphthoate, respectively.The effect of substituents and ring-chain tautomerism on the rates has been considered.For the o-acylbenzoates the initial state is the ring-chain tautomerism equilibrium mixture and the rate-determining step is the intramolecular attack of the anion of the normal ester.For normal 8-acyl-1-naphthoates the rate-determining step is the ionisation of the normal esters; for the corresponding pseudo esters, the rate-determining step is the isomerisation of the pseudo to the normal ester.
- Bowden, Keith,Chehel-Amiran, Mohsen
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p. 2035 - 2038
(2007/10/02)
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