Pd-Catalyzed a-Substitution of Enolates and Related Derivatives

In 1987, the senior author and his coworkers reported the first-generation protocol (Protocol I) [269] involving (i) conversion of enones to carbonyl-protected a-iodoenone derivatives [270], (ii) Pd- or Ni-catalyzed organozinc cross-couphng. 

R and R = C groups. R = alkyl, alkenyl, aryl, and alkynyl groups. X = I, Br, OSO2R, or alternative leaving group. 

1) Certain heteroaryl iodides that may be viewed as ot-iodoenones, most notably iodouracils, are known to readily undergo Pd-catalyzed cross-coupling without their decomposition or other unwanted side reactions presumably due to their aromaticity. These reactions must be strictly distinguished from those nonaromatic oi-iodoenones that are discussed in this study. 

In this section, attention is focused on the recent advances and notable applications in the Pd-catalyzed a-substitution reactions of enolates and related derivatives. Although Tsuji-Trost allylations and propagylations are not presented here, an overview of them were already comprehensively discussed and summarized in Chapter V.2.1 of the Handbook of Organopalladium Chemistry fc/r Organic Synthesis [279] 

Liu and Hartwig [290] reported in 2004 the Pd-catalyzed arylation of trimethylsilyl keteneimides in which the Pd(dba)2/P(tBu)3-catalyzed reaction of aryl bromides 

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