- A stereoselective synthesis of methyl trans-3-(2,2-dichloroethenyl)- 2,2-dimethylcyclopropanecarboxylate
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A convenient method is described for the stereoselective synthesis of methyl trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate (5) via methyl 3,3-dimethyl-4,6,6,6-tetrachlorohexanoate (4) as a key intermediate, which was obtained by addition of carbon tetrachloride to methyl 3,3-dimethyl-4-pentenoate (3). Treatment of (4) with sodium methoxide in a single-vessel via methyl 4,6,6-trichloro-3,3-dimethyl-5-hexenoate (6) gave trans-rich (5) in excellent yield.
- Ma, Jun'an,Huang, Runqiu,Cheng, Junran,Shao, Ruilian,Li, Zaiguo
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p. 1653 - 1659
(2007/10/03)
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- Process for preparing halogenated compounds
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A process for preparing halogenated compounds of formula RCY(Z)CH2 CH(X)C(CH3)CH2 COR1 where X, Y and Z are halo, R is alkyl, halo, haloalkyl or aryl, and R1 is hydroxy, halo, alkoxy, alkyl or haloalkyl, or the residue of a pyrethroidal alcohol, in which a compound of formula CH2 =CHC(CH3)2 COR1 is reacted with a sulphonyl halide of formula RCY(Z)SO2 X. The process avoids the use of volatile halocarbons in the production of valuable intermediates for insecticides.
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