Cross-coupling reactions carbometalation

Chinkov, N. Tene, D. Marek, I. Carbometalation Reaction. In Metal-Catalyzed Cross-Coupling Reactions, 2nd ed. Diederich, F., de Meijere, A., Eds. Wiley-VCH Weinheim, 2004 pp 395M78. 

The Pd-catalyzed cross-coupling reaction of vinyl(2-pyridyl)silanes 5.48 with organic halides gave substituted vinyl(2-pyridyl)silanes 5.49 in high yields. The mechanism of this reaction involves the carbometallation pathways (Scheme 5.18). 

Hydrometallation-cross-coupling and carbometallation-cross-coupling tandem protocols and other alkenyl-aryl, alkenyl-alkenyl, and alkenyl-alkynyl coupling reactions double metal catalysis... 

An indium-mediated carbometalation of o-iodoynamides 121 provided -alkylideneoxindoles 123 via 122 <04OL2825>. Indium intermediate 122 could also be utilized in a palladium-catalyzed cross-coupling reaction to give Z-alkylideneoxindoles. 

Yanada R, Obika S, Oyama M, Takemoto Y (2004) Stereoselective synthesis of 3-aUtylide-neoxindoles using tandem in-mediated carbometalation and Pd-catalyzed cross-coupling reaction. Org Lett 6 2825-2828... 

B.iv.a. p, P -Substituted Alkenybnetals. Carbometallation reactions of 1-alkynes, most notably carboalumination and carbocupration,t collectively provide a powerful route to the synthesis of /3,j8 -substituted alkenylmetals. The alkenylmetals generated in situ may be used directly for Pd- or Ni-catalyzed cross-coupling with aryl electrophiles (Protocol 1). One prototypical example of the carbometallation-cross-coupling tandem process is shown in Scheme... 

Even today, carotenoids and other natural products represented by 1 and/or 2 are synthesized by using the Wittig and related carbonyl oleflnation reactions that are often not highly stereoselective, thus requiring delicate and tedious separations. Carbometallation reactions of alkynes, " ° especially the Zr-catalyzed carboalumination discovered in 1978,[236].[237] jjj conjunction with Pd-catalyzed cross-coupling have provided a totally different carbometallation-cross-coupling tandem protocol for the synthesis of 1 and 2 (Scheme 59). 

An interesting sequential reaction, consisting of an intermolecular alkene carbometallation and subsequent intermolecular alkyne cross-coupling, has been reported (Scheme 8.87) [601]. Starting from an immobihzed tropane framework 459, stoichiometric carbopalladation yields a stable organopalladium intermediate, which in the presence of copper(I) iodide undergoes coupling with an added terminal acetylene. 

An interesting sequential reaction consisting of an intermolecular alkene carbometallation and subsequent intermolecular alkyne cross-coupling has been reported by... 

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