Electrophile alkenyl

Oxidative addition reactions of Cp2Zr derivatives with alkenyl electrophiles. 

The Pd-catalyzed reaction of alkynylzincs with alkenyl electrophiles is generally dependable and widely applicable. However, recent studies with 1,1-dihalo-l-alkenes, 1,2-dihaloalkenes, and other alkenyl halides have indicated that the presence of two proximal... 

TABLE 5. Natural products synthesized since 1996 by using the Pd-catalyzed alkynylation of alkenyl electrophiles with alkynylmetals containing Zn or Mg... 

Alkenyl electrophiles, addition to zirconacycles, 10, 281 Alkenyl ethers... 

Arylboronic acids are also efficient reagents for the arylation of 1-alkenyl halides and tri-flates. The first such cross-coupling reactions between arylboronic acids or esters and 1-alkenyl electrophiles were performed in the presence of a palladium catalyst and a base... 

Alkoxystannanes. Only few examples are known of the coupling reactions with allylic and alkenyl electrophiles.f ... 

The synthesis of alkene-substituted arenes by cross-coupling can, in principle, be achieved either by the reaction of alkenyhnetals with aryl halides and related electrophiles or by that of arylmetals with alkenyl electrophiles. For the sake of simplicity, the former reaction is termed the alkenyl-aryl coupling, while the latter is termed the aryl-alkenyl coupling in this Handbook. Similar terms may be devised by linking the carbon groups of the organometal and organic electrophile with a dash in this order. 

B.iii.b. (Z)- Substituted Alkenylmetals. The stereodefined (Z)-/3-substituted aUcenyl-metals can generally be prepared by either metallation or metallation-transmetallation of the corresponding (Z)-alkenyl electrophiles. However, several other methods are notable.f i [5 ] P5] a stereoselective synthesis of (Z)-alkenylboranes via hydroboration... 

An alternative approach to the synthesis of stereodefined arylated alkenes by the Pd-catalyzed cross-coupling involves the reaction of arylmetals with alkenyl electrophiles, i.e., aryl-alkenyl coupling (Sect. A). Table 8 summarizes some representative examples of the Pd-catalyzed aryl-alkenyl coupling reactions. 

The reaction of arylboron compounds with alkenyl electrophiles has not been extensively investigated, and unfavorable results associated with fair yields in Pd-catalyzed... 

Pd-Catalyzed Coupling of Vinylmetals with Alkenyl Electrophiles ... 

Alkenylmetals containing Mg, Zn, B, Al, Si, Sn, and Zr have been successfully coupled with alkenyl electrophiles, mainly halides and triflates. Alkenyl electrophiles of all eight possible structural types have been used in these coupling reactions as shown in Table 10. 

TABLE 10. Pd-Catalyzed Coupling of (E)-/3-Substituted Alkenylmetals with Alkenyl Electrophiles ... 

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