Allylic Suzuki coupling

Similar to the case of Suzuki couplings (6.1.2), ally lie alkylations can also be run in neat water as solvent in the presence of surfactants. In addition to the general solubihzation effect, the amphiphiles may also have a specific influence on the reaction rate. For example, the reaction of the P-ketoester substrate on Scheme 6.22 with allyl acetate, catalyzed by [Pd(PPh3)4] was only slightly accelerated by the anionic SDS (1.5 h, 18 % yield), however, the reaction rate dramatically increased in the presence of the cationic CTAB and the neutral Triton X-100 detergents, leading to 74 % and 92% yields in 1.5 h and 5 min ( ), respectively [51]. Several other carbonucleophiles were alkylated in such emulsions with excellent yields. 

Ellman used silyl chemistry for the direct linkage of aromatics onto the solid support by converting an aryl bromide to aryl lithium and reacting this with a silyl resin.90 It is the production of the silyl resin that is of interest in the context of this review, since an in situ Suzuki coupling was used to link the allyl silane to bromomethyl polystyrene resin (Scheme 40). 9-BBN is used to carry out the regioselective hydroboration, and this is linked to the resin with palladium catalysis in the usual way. After brief exposure of this... 

A less extensive study of the reaction of boronic acids with different structural characteristics - aryl, vinyl, allyl, and alkyl- with iodobenzene on Pd-KF/Al203 was also undertaken (eq. 3) (Table 4), Only the allylic boronic acid, 3-propenylboronic acid, did not undergo the Suzuki coupling although it was largely consumed. 

If 2,3-dibromo propene is used as an allylic substrate the substitution product 71 can be either isolated or, after addition of additives and adjustment of the reaction conditions, 71 can readily react in cross-coupling reactions with alkynes (Sonogashira coupling), stannanes (Stille coupling), or boronic acids and boronates (Suzuki coupling) to provide the sequential allylic substitution-cross-coupling products 72-78 in moderate to good yields (Scheme 23). 

Sequential allylic substitution-Stille coupling" Sequential allylic substitution-Suzuki coupling"... 

Scheme 24 Sequential allylic substitution-Sonogashira and Suzuki coupling [80]...

When propargyl allyl ethers are subjected to transition metal-catalyzed enyne cyclization reactions, 3-alkylidene-substituted tetrahydrofurans are usually formed. A useful variation of this scheme is the Pd(0)-catalyzed tandem enyne cyclization/Suzuki coupling reaction with various arylboronic acids (Equation 90) <2005JOC1712>. The stereoselectivity of this reaction is explained by invoking a chairlike transition state. 

Suzuki couplings. Pd-catalyzed reactions of B-allyl borate complex derived from 6-methoxy-9-borabicyclo[3.3.1]nonane with aryl triflates give allylarenes. This technique broadens the scope of the Suzuki coupling to allow transfer of Me, TMSCHj, and alkynyl groups which has eluded conventional manipulations. 

Phosphino)amines and their complexes have been shown to be efficient catalysts for the palladium-catalyzed Suzuki coupling reaction of chloroarenes,449 rhodium-catalyzed hydroformy-lations458 and asymmetric hydrogenations,463,466 allylic substitution reactions,47, 472 conversion of isocyanates to isocyanurates,478 and as ethylene polymerization catalysts.479... 

Two complementary methods for allylation of arene derivatives are Suzuki coupling with aUyl acetates, and converting allyl acetates to aUylindium reagents in situ for couping with ArX. ... 

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