- A facile access to pyrroles from amino acids via an aza-Wacker cyclization
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(Chemical Equation Presented) A facile and efficient synthesis of pyrroles from readily available amino acids is described. The key step in the method is an aza-Wacker oxidative cyclization catalyzed by palladium(II)/Cu(OTf) 2. A series of pyrroles were obtained by this method under mild conditions.
- Zhang, Zuhui,Zhang, Jintang,Tan, Jiajing,Wang, Zhiyong
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p. 5180 - 5182
(2008/12/20)
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- Synthesis and field bioassay of the Israeli pine bast scale, Matsucoccus josephi, female sex pheromone
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We report the first synthesis of the two components of the female sex pheromone of Matsucoccus josephi (2E,4E,8E)-4,6-dimethyl-2,4,8-decatrien-7-one (1) and (2E,4Z,8E)-4,6-dimethyl-2,4,8-decatrien-7-one (2) utilizing the Reformatzky and Wittig reactions as key steps. A mixture of 1 and 2 and the separate isomers were bioassayed in a pine forest indicating that E isomer 1 is much more active than 2 and is also a kairomone for a predator.
- Zegelman, Lev,Hassner, Alfred,Mendel, Zvi,Dunkelblum, Ezra
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p. 5641 - 5644
(2007/10/02)
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- Acyclic Stereocontrol through the Thio-Claisen Rearrangement of Precursors bearing a Chiral Centre adjacent to Carbon 1
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The Claisen rearrangement of precursors bearing a stereogenic centre adjacent to carbon 1 of the pericyclic nucleus has been investigated in the sulfur series.Dithioesters having a methyl and various alkyl or alkenyls groups on the β-carbon were deprotonated by LDA.The resulting enethiolates were allylated on sulfur to give S-allyl ketenedithioacetals.The thio-Claisen transposition of the latter compounds was achieved either at room temperature or at 101 deg C to afford good yield of allylated dithioesters.Diastereomeric selectivities up to 95:5 have been observed.These results have been explained by a steric effect and correlated to allylic strain values.
- Desert, Stephane,Metzner, Patrick,Ramdani, Mohamed
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p. 10315 - 10326
(2007/10/02)
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