Structural Elucidation and Synthetic Application of Organozinc reagents with Pronounced Nucleophilic Reactivity

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(1) The new synthetic reaction of unsymmetrically substituted ketones was developed. The reaction proceeds via the three-component connection reaction of allylic benzoates, carbon monoxide, and organozincs by the catalysis of palladium at room temperature under 1 atm of carbon monoxide. The reaction shows quite characteristic regio (alpha-and gamma-) -and stereoselectivity (inversion of configuration) with respect to the allylic moiety. The reaction is applicable to the combination of a wide structural variety of allylic substrates (benzoates, phosphates) and organozincs (IZn (CH_2)_n X,X=CO_2 Et, CN ; octylzinc iodide, diethylzinc).(2) The new method of umpolung of pi-allylpalladium was developed. The umpolung of pi-allylpalladium takes place cleanly by treatment with diethylzinc via allyl-ethyl transmetallation reaction. The reaction can be catalytic with respect to palladium and the mixture of an allyl benzoate, a carbonyl compound (aldehyde, ketone, ester), diethylzinc, and tetrakis (triphenylphosphine) palladium provides the corresponding homoallyl alcohol in quite high yield. The reaction displays high regio-and stereoselectivity, having been not observed for the allylation with allyzinc halides.