- I2-catalyzed regioselective oxo- and hydroxy-acyloxylation of alkenes and enol ethers: A facile access to α-acyloxyketones, esters, and diol derivatives
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I2-catalyzed oxo-acyloxylation of alkenes and enol ethers with carboxylic acids providing for the high yield synthesis of α-acyloxyketones and esters is described. This unprecedented regioselective oxidative process employs TBHP and Et3/s
- Reddi, Rambabu N.,Prasad, Pragati K.,Sudalai, Arumugam
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supporting information
p. 5674 - 5677
(2015/02/19)
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- Enantioselective synthesis of cyclic sulfamidates via Pd-catalyzed hydrogenation
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Using Pd(CF3;CO2)2/(S,S)-f-binaphane as the catalyst, an efficient enantioselective synthesis of cyclic sulfamidates was developed via asymmetric hydrogenation of the corresponding cyclic imines in 2,2,2-trifluoroethanol at room temperature with high enantioselectivities (up to 99% ee).
- Wang, You-Qing,Yu, Chang-Bin,Wang, Da-Wei,Wang, Xiao-Bing,Zhou, Yong-Gui
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supporting information; experimental part
p. 2071 - 2074
(2009/04/18)
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- A Systematic Study on the Bakers'Yeast Reduction of 2-Oxoalkyl Benzoates and 1-Chloro-2-alkanones
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The bakers' yeast reduction of a series of 2-oxoalkyl arenecarboxylates (1a-f) (R=CH3 to n-C6H13; X=H) and the phenyl-modified derivatives (1g-l) (R=n-C5H11, X=OH, CH3, F, Cl, Br, or I) as well as 1-chloro-2-alkanones R(C=O)CH2Cl (6a-f) (R=CH3 to n-C6H13) were systematically investigated.The substrate specificities, configuration and percentee of the reduction products were found to be highly dependent on the length of the alkyl group (R) and the α substituent.Thus, the benzoates 1a-f gave optically active 2-hydroxyalkyl benzoates (2a-f) (R, configuration, percentee) (a: CH3, S, 99; b: C2H5, S, 98; c: C3H7, S, 26; d: n-C4H9, R, 55; e: n-C5H11, S, 15; f: n-C6H13, S, 63) in 11-91percent yields.Among the modification experiments of the phenyl group, 1g-l, the p-iodo substituent markedly increased the ee from 15 to 71percent, although the yield was rather lowered (22percent yield).The reduction of α-chloro ketones 6a-f also gave optically active 1-chloro-2-alkanols (7a-f) in 16-69percent yields.
- Sakai, Takashi,Wada, Kou,Murakami, Takahiko,Kohra, Kiichiro,Imajo, Norihisa,et al.
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p. 631 - 638
(2007/10/02)
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- New Synthesis of α-Benzoyloxy Aldehydes. Application to the Stereoselective Synthesis of Conjugated (E,E)-Dienoic Esters
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A new synthetic method for the preparation of secondary α-benzoyloxy aldehydes (5a-d) and its use in the stereoselective synthesis of conjugated (E,E)-dienone (14) and dienoic esters (9b, 9c, 11, 15b, and 15c) were studied.Two-phase (benzene-H2O) reaction of RCH2CHXCHO (R=CH3, C3H7, C5H11, C7H15; X=Cl, Br) with sodium benzoate (4) in the presence of a catalytic amount of tetrabutylammonium bromide gave the corresponding α-benzoyloxy aldehydes (5a-d) in moderate yields.Compounds 5a-d were converted to γ-benzoyloxy-α,β-unsaturated carbonyl compounds or esters (7b, 7c, 10, 12, 13b, and 13c) either by the TiCl4/py-catalyzed condensation with malonate or acetoacetate or by the Wittig reaction with Ph3P=CHC(O)CH3 and Ph3P=CHCO2Et.Treatment of these compounds with 5 mol percent of (Ph3P)4Pd in refluxing THF afforded the corresponding conjugated (E,E)-dienones and dienoic esters stereoselectively.The reaction sequence was further extended to the stereoselective synthesis of ethyl (2E,4E,6E)-2,4,6-dodecatrienoate (18) and pellitorine (21).
- Sakai, Takashi,Seko, Katsuhiko,Tsuji, Akihiro,Utaka, Masanori,Takeda, Akira
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p. 1101 - 1106
(2007/10/02)
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