Palladium -catalyzed reactions function

Various telomers and oligomers now available by the palladium-catalyzed reactions of butadiene with various nucleophiles are very useful compounds for organic synthesis, because these compounds have functional groups at one end and terminal double bonds at the other end. Several natural products have been synthesized from the telomers. 

Palladium-catalyzed coupling reactions are very efficient for the introduction of new carbon- carbon bonds onto molecules attached to solid support. The mild reaction conditions and compatibility with a broad range of functionalities and high reaction yields, have made this kind of transformation a very common tool for the combinatorial synthesis of small organic molecules. The literature for synthetic methods of palladium-catalyzed reactions on solid supports has recently been reviewed [237-239]. 

A recent paper explored the 1,2-functionalization of the allene moiety in monocyclic P-lactam allenynol derivatives under palladium-catalyzed reaction conditions <02CEJ1719>. Remarkably, a novel domino process, namely allene cyclization/intramolecular Heck reaction... 

The palladium-catalyzed reaction of diboron with allyl acetates or chlorides is a convenient alternative to transmetallation method for the synthesis of functionalized boronates. The reaction of diboron 119 with allyl acetates309-312 smoothly occurred without the assistance of a base, whereas the presence of AcOK was critical for the coupling with allyl chlorides313 (Equation (57)). The boron atom coupled with the less-hindered terminal carbon giving the thermally stable (if)-allyl boronates. Thus, the (E)- and (Z)-cinnamyl acetate, chloride (entries 1-4), and their secondary derivatives (entries 7 and 8), all afforded an (if)-cinnamyl boronate. The borylation of prenyl acetate was slow (entry 6), but the corresponding chloride (entry 5) and tertiary derivative (entry 9) worked well for the same purpose (Equation (58)).309,310... 

Tin-functionalized 1-phosphanorbornadienes can be prepared from tin-substituted alkynes using this type of methodology. Subsequent tin-halogen exchange affords the corresponding halo derivatives, which may be further elaborated using palladium-catalyzed reactions such as Stille coupling, for example (see Section 3.15.12.1.2). 

The use of alcohol tetraene substrate 28 in this reaction made it possible to determine the stereochemistry of the overall 1,4-addition of the carbon and oxygen functions to the diene [Eq.(27)] [46]. Palladium-catalyzed reaction of 28 in THF at reflux afforded product 30 in... 

In the second approach an ailylsiiane was employed as carbon nucleophile in the side chain. Ailylsilanes have been frequently used as masked allyl carbanions, usually in reactions with a keto function. Palladium-catalyzed reaction of ailylsiiane 57 with LiCl under similar conditions as used for the other intramolecular 1,4-oxidations afforded 58 (equation 22). Interestingly, the carbochlorination over the diene was highly 1,4-syn... 

It bonds with the C=C bond tilted somewhat with respect to the surface normal and the measured structure is in accordance with that calculated using density functional theory [55, 56]. The saturation coverage of vinylidene at 300 K is 1 ML. Furthermore, a vinylidene overlayer is found on the surface during palladium-catalyzed reactions of acetylene [13], which suggests that acetylene cyclotrimerization proceeds in the presence of a vinylidene-covered surface, rather... 

Over the past 30 0 years, organopalladium chemistry has found widespread use in organic synthesis, and has been described in detail in a number of useful and informative books [1]. Palladium catalysts facilitate unique transformations that carmot be readily achieved using classical techniques, and in many cases palladium-catalyzed reactions proceed under mild reaction conditions and tolerate a broad array of functional groups. As such, the use of palladium catalysts for the synthesis of important, biologically active heterocyclic compounds has been the focus of a considerable amount of research [2],... 

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