- Rasta Resin-TBD-Catalyzed γ-Selective Morita-Baylis-Hillman Reactions of α,γ-Disubstituted Allenones
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Rasta resin-TBD (RR-TBD) was found to be an efficient organocatalyst for γ-selective Morita-Baylis-Hillman reactions between α,γ-disubstituted allenones and aryl aldehydes. In these reactions the heterogeneous nature of RR-TBD greatly facilitated product isolation since the catalyst could be separated simply by filtration.
- Ma, Shuang,Yang, Yun-Chin,Toy, Patrick H.
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supporting information
p. 1732 - 1736
(2015/07/20)
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- The synthesis of (+)-Allopumiliotoxin 323B′
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This paper describes the synthesis of (+)-allopumiliotoxin 323B′ (1) using the intramolecular [3 + 2]-cyclo-addition reaction of the (Z)-N-alkenylnitrone 4. This synthesis began with (R)-tert-butyl-3-hydroxy-pent-4-enoate [(R)-13] which was obtained by enzymatic resolution with Amano PS lipase. A series of manipulations gave intermediate 17 and in situ coupling with 4-benzoyloxybutanal lead to the (Z)-N-alkenylnitrone 4 which underwent an intramolecular [3 + 2]-cycloaddition reaction to give the isoxazolidine 3 as the major cycloadduct. Isoxazolidine 3 provided the piperidinone 24 which upon diastereofacial selective addition of MeMgBr gave the required tertiary alcohol 25. Formation of the indolizidine core 2 was achieved by an intramolecular SN2 reaction. The side chain was assembled from a Wittig reaction between the phosphorane 8 and the enantiomerically pure aldehyde 9. Further modifications afforded the aldehyde 7 which underwent an aldol condensation with the potassium enolate of the indolizidone core 2. Dehydration gave the enone 37 which was converted into the anti-diol 38 by intramolecular hydride reduction. Finally, deprotection of the BOM protecting group gave (+)-allopumiliotoxin 323B′ (1).
- Tan, Choon-Hong,Holmes, Andrew B.
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p. 1845 - 1854
(2007/10/03)
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- Facile synthesis of (-)-serricornin by means of palladium-catalyzed hydrogenolysis of alkenyloxiranes
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Chiral synthesis of (-)-serricornin by using palladium-catalyzed stereoselective hydrogenolysis of the alkenyloxirane to the homoallylic alcohol with formic acid as a key step was carried out.
- Shimizu,Hayashi,Ide,Oshima
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p. 2991 - 2998
(2007/10/02)
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- Pheromones, 65. - Identification of the Volatile Components of the Mandibular Gland Secretion of the Ant Manica rubida: Structure Elucidation, Synthesis, and Absolute Configuration of Manicone
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By means of gas chromatography and mass spectrometry, manicone, (4E)-4,6-dimethyl-4-octen-3-one (1), was identified as the main component of the mandibular gland secretion of the ant Manica rubida.In addition the presence of homomanicone (2), bishomomanicone (3), normanicone (7), and a few aliphatic aldehydes and ketones was also evident in the gland.Racemic 1, 2, and 7 and optically active dihydromanicone (4), were synthesized.The (S) configuration of 1 was determined by complexation gas chromatography, on a chiral phase, of 4 as well as of the hydrogenation products of racemic and natural 1.
- Bestmann, Hans Juergen,Attygalle, Athula B.,Glasbrenner, Juergen,Riemer, Roland,Vostrowsky, Otto,et al.
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