Selected regiocontrolled transformations applied to the synthesis of (1S)-cis-chrysanthemic acid from (1S)-3,4-epoxy-2,2,5,5-tetramethylcyclohexanol
作者:Alain Krief、Humaira Y. Gondal、Adrian Kremer
DOI:10.1039/b808695h
日期:——
(1S)-cis-Chrysanthemic acid has been prepared in a few steps with complete control of the relative and absolute stereochemistry using regiocontrolled epoxide ring opening, diol mono-oxidation and cyclopropanation.
Competing cyclopropane over epoxide formation from γ-halogeno-δ-hydroxy-ketones
作者:Alain Krief、Adrian Kremer
DOI:10.1016/j.tetlet.2010.02.003
日期:2010.4
Carbocyclization has been selectively achieved over epoxide formationfrom a γ-chloro-δ-hydroxy-ketone in the presence of a lithiumamide or using a different strategy in which the related silyloxyenol ether bearing an iodine atom at gamma-position and a silyloxy group in delta-position is reacted with tetrabutylammonium fluoride. These approaches take advantage of (i) the poor reactivity of the intermediate
Diastereoselective Epoxidation of Compound Bearing a Cyclohex-3-enol Moiety: Application to the Enantioselective Synthesis of (1R)-trans-Chrysanthemic Acid and (1R)-cis-Deltametrinic Acid
作者:Alain Krief、Stéphane Jeanmart、Adrian Kremer
DOI:10.3987/com-08-s(n)117
日期:——
We disclose the synthesis of enantiomeric (1S)-cis- and (1R)-cis-chrysanthemic acids precursors of S-bioallethrin and deltamethrin the most active indoor and outdoor insecticides respectively. It involves an original strategy which takes advantage of the complete stereocontrolled epoxidation of an homoallylalcohol and the synthesis in the same pot of precursors of each of the two enantiomers of cis-chrysanthemic acid, bearing functional groups possessing similar reactivity but having different structural behavior which allow their easy separation.
Novel enantioselective syntheses of optically active (1R)-cis- and (1R)-trans-chrysanthemic acids.
Dimethyl dimedone, a non chiral and cheap compound, has been converted to the optically actives 1-(R)-cis- and 1-(R)-trans-chrysanthemic acids possessing high economic value. These processes involve as the key steps (i) a cyclopropanation reaction (ii) a Grob fragmentation and (iii) a lipase monitored hydrolysis of a prochiral diacetate.
KRIEF, A.;SURLERAUX, D.;FRAUENRATH, H., TETRAHEDRON LETT., 29,(1988) N 47, C. 6157-6160