Carbopalladation synthetic applications

IV Pd-CATALYZED REACTIONS INVOLVING CARBOPALLADATION C. SYNTHETIC APPLICATIONS... 

The carbopalladation is a central reaction in organopalladium chemistry and is extensively presented in Part IV. hi most reactions, a discrete organopalladium intermediate adds to a donble or triple bond. In this section, the reaction of an alkyl iodide with di-ethylzinc in the presence of a palladium(O) catalyst is presented. Such reaction conditions generate an alkyl radical that readily adds intramolecularly to a double bond, leading to an organozinc derivative (Scheme 1). The combination of a radical cyclization with the formation of an organometallic product allows new synthetic applications that will be discnssed. Closely related Ni-catalyzed cyclizations will also be briefly presented. 

Cascade intermolecular carbopalladations of alkynes followed by intramolecular trapping with electrophiles represent not only a novel type of organic transformation involving vinylpalladium intermediates, but also provide synthetically useful routes toward differently substituted indenols, indanones, indenones, and naphthy-lamines." Although these protocols are restricted to the intramolecular trapping with electrophiles, a wide application of this methodology toward the synthesis of various types of complex carbocychc compounds may be anticipated in the near future. 

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