Iodoarenes Stille coupling

Innumerable aryl- and heteroarylstannanes take part in Stille couplings with halopyridines. In one such example, the union of arylstannane 106 and 4-bromopyridine furnished arylpyridine 107 [90], Arylstannane 106 was prepared from the Pd-catalyzed reaction of hexabutylditin with iodoarene 105, which arose from aminobenzolactam 104 via a Sandmeyer reaction. 

Kantam, M.L., Roy, M., Roy, S. et al. (2006) Layered double hydroxide-supported nanoplatinum an efficient and reusable ligand-free catalyst for Heck and Stille coupling of iodoarenes. Synlett, 2266-8. 

Any substrate that undergoes oxidative addition onto Pd can in principle be coupled with any transferable group using an organotin compound. The Stille coupling is the most used example in synthesis. It is a very efficient reaction that allows to couple a vinyl- or an alcynyltin derivative with a iodoalkene or iodoarene, the reaction being catalyzed by Pd ... 

On the other hand, even the recently prepared Herrmann-Beller catalystf still requires higher temperatures for efficient coupling rates of the Heck reaction. Interestingly, the complexation of chloroarenes with the Cr(CO)3 fragment activates the arene-chlorine bond considerably toward the oxidative addition. Thus, Cr(CO)3 complexed chloroarenes react about 15 times faster than iodoarenes in Pd-catalyzed cross-couphng reactions under mild conditions, in particular in Pd/Cu-catalyzed cross-couplings with terminal acetylenes in refluxing THF and/or tertiary amines (Scheme 36). ... 

An analogous 5-exo-dig carbopalladation, performed on an iodoarene with an ortho-alkynylamino substituent in the presence of hexabutyldistannane, produces an alkenyl-stannane, which undergoes a second cyclization by intramolecular Stille cross-coupling with the second o-iodoaniline moiety in the molecule. The hnal product, though, arises by double bond migration (Scheme 25, Eq. 1). Alternatively, a 1,1-disubstituted aUcene... 

Scheme 9.28 The Stille cross-coupling of alkynyltin 82 with the iodoarene 83 using the iminophosphine-ligated Pd catalyst 81 [247].

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