- Pd(ii)/Zn co-catalyzed chemo-selective hydrogenation of α-methylene-γ-keto carboxylic acids
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An efficient Pd/Zn co-catalyzed chemo-selective hydrogenation of α-methylene-γ-keto carboxylic acids is described. This methodology offers a divergent synthesis of α-methyl-γ-keto carboxylic acids, α-methylcarboxylic acids, and lactones starting from α-me
- Zhang, Xuexin,Gao, Yang,Laishram, Ronibala Devi,Li, Kangkui,Yang, Yong,Zhan, Yong,Luo, Yang,Fan, Baomin
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p. 2174 - 2181
(2019/02/27)
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- First total synthesis of prionoid E, A bioactive rearranged secoabietane diterpene quinone from Salvia prionitis
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The first total synthesis of prionoid E (1), a rearranged secoabietane diterpene quinone isolated from Salvia prionitis, was achieved efficiently by means of Wacker oxidation (Scheme 5) and aldol condensation (Scheme 7) as the key steps in the synthetic sequence. Thus 1 was prepared in 15 steps in 3.7% yield starting on one hand from anisole (=methoxybenzene) and methylsuccinic anhydride (=dihydro-3-methylfuran-2,5-dione) via 4 (Scheme 3 and 5), and on the other hand from 2-hydroxy-2-methylpropanoic acid via 5 (Scheme 6). Copyright
- Deng, Fei,Xu, Jun,Zhao, Min,Liu, Hong-Ying,Ye, Yang,Zhang, Jin-Sheng
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experimental part
p. 1326 - 1334
(2011/09/21)
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- A simple synthesis of α-methyl-γ-keto acids
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The reaction of the anion derived from α-marpholinonitriles with methyl acrylate in excess of NaH in DMF gives γ-keto acids in high yield. This process is highly convenient for the synthesis of various α-substituted-γ-keto acids, which can be easily converted to naturally occurring α-substituted -γ-lactones.
- Pawar,Waghmare,Lokhande
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p. 2549 - 2551
(2007/10/03)
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- Enantioselective TADMAP-catalyzed carboxyl migration reactions for the synthesis of stereogenic quaternary carbon
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The chiral, nucleophilic catalyst TADMAP [1, 3-(2,2,2-triphenyl-1- acetoxyethyl)-4-(dimethylamino)-pyridine] has been prepared from 3-lithio-4-(dimethylamino)pyridine (5) and triphenylacetaldehyde (3), followed by acylation and resolution. TADMAP catalyzes the carboxyl migration of oxazolyl, furanyl, and benzofuranyl enol carbonates with good to excellent levels of enantioselection. The oxazole reactions are especially efficient and are used to prepare chiral lactams (23) and lactones (30) containing a quaternary asymmetric carbon. TADMAP-catalyzed carboxyl migrations in the indole series are relatively slow and proceed with inconsistent enantioselectivity. Modeling studies (B3LYP/6-31G*) have been used in qualitative correlations of catalyst conformation, reactivity, and enantioselectivity.
- Shaw, Scott A.,Aleman, Pedro,Christy, Justin,Kampf, Jeff W.,Va, Porino,Vedejs, Edwin
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p. 925 - 934
(2007/10/03)
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- Development of Chiral Nucleophilic Pyridine Catalysts: Applications in Asymmetric Quaternary Carbon Synthesis
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TADMAP (1a), a new chiral DMAP catalyst, has been designed to place a C(3)-benzylic trityl group over one face of the pyridine ring, while a C(3)-benzylic acetoxy group creates a chirotopic environment on the other face. TADMAP was prepared in four steps
- Shaw, Scott A.,Aleman, Pedro,Vedejs, Edwin
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p. 13368 - 13369
(2007/10/03)
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- Acylation of anisole with methylsuccinic anhydride catalysed by zeolites
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The zeolite-catalysed acylation of anisole with methylsuccinic anhydride gave a mixture of products. The main component was 4-hydroxy-4,4-bis-(4-methoxyphenyl)-2-methyl-γ-butyrolactone, which was isolated in 25% yield; the expected keto acids were not for
- Gaare, Kristin,Akporiaye, Duncan,Holm, Kjetil,Skattebol, Lars
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p. 1229 - 1233
(2007/10/03)
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