Domino reactions Suzuki/Mizoroki-Heck

Recently, Zhou and Larock [57] have also used a domino Mizoroki-Heck/Suzuki process in their syntheses of several tamoxifen analogues. They described a three-component coupling reaction of readily available aryl iodides, internal alkynes and arylboronic acids to give the expected tetrasubstituted olefins in good yields. For instance, the treatment of a mixture of iodobenzene, alkyne 92 and phenylboronic acid with catalytic amounts of PdCl2(PhCN)2 gave 93 in 90% yield. In this process, substituted aryliodides and... 

In most of the palladium-catalysed domino processes known so far, the Mizoroki-Heck reaction - the palladium(0)-catalysed reaction of aryl halides or triflates as well as of alkenyl halides or triflates with alkenes or alkynes - has been apphed as the starting transformation accordingly to our classification (Table 8.1). It has been combined with another Mizoroki-Heck reaction [6] or a cross-coupling reaction [7], such as Suzuki, Stille or Sonogashira reactions. In other examples, a Tsuji-Trost reaction [8], a carbonylation, a pericyclic or an aldol reaction has been employed as the second step. On the other hand, cross-couphng reactions have also been used as the first step followed by, for example, a Mizoroki-Heck reaction or Tsuji-Trost reactions, palladation of alkynes or allenes [9], carbonylations [10], aminations [11] or palladium(II)-catalysedWacker-type reactions [12] were employed as the first step. A novel illustrative example of the latter procedure is the efficient enantioselective synthesis of vitamin E [13]. 

In domino transition-metal-catalysed processes, cross-coupling reactions can also be nsed as the starting transformation. Most often, Suzuki, Stille and Sonogashira reactions are employed in this context. They can be combined with a Mizoroki-Heck reaction and other palladium-catalysed transformations. 

A palladium(II)-catalysed Heck-Mizoroki/Suzuki-Miyaura domino reaction of arylboronic acids with vinyl ethers (34), catalysed by (CF3C02)2Pd and using p-benzoquinone (p-BQ) as reoxidant, has been developed. The key importance of the... 

Recently, Yahiaoui et al. developed a chelation-controlled palladium-catalyzed Heck-Mizoroki/Suzuki-Miyaura domino reaction involving metal-coordinating dimethylaminoethyl vinyl ethers and various electron-deficient and electron-rich arylboronic acids by the use of p-Bq as the oxidant [22] (Scheme 6.13). The two-carbon tethered dimethylamino moiety, which could combine with p-Bq for the stabilization of the o-alkylpalladium(II) intermediate 56 and formation of the dia-rylated products 57, is assumed to be crucial for avoiding the formation of Heck products 58. 

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