Pyrethrolone synthesis

This reaction was used in a synthesis of pyrethrolone (1) from butadiene (scheme... 

Even from the modem point of view the natural pyrethrin I is, in certain respects, still a quite good insecticide. Therefore a simple synthesis for pyrethrolone 557 is a challenge for applied chemists. But so far those syntheses start from allethrolone, which has to be ozonized to an aldehyde 358 for elongation to the Z/E-mixture of the conjugated pentadienyl side chain [745, 746] Reaction scheme 241. This mixture was separated by chromatographic methods. Apparently, nature is still the better chemist in this case. 

The same method of diene formation was applied to the synthesis of pyrethrolone (Equation 13), an alcoholic component of naturally occuring pyrethroids [14]. 

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