Triflate with Grignard reagents

Oxidative addition to Pd(0) is an important step in many C—C bond-forming reactions catalyzed by Pd. These include the cross-coupling of vinyl or aryl halides or triflates with Grignard reagents or organostannanes ... 

Scheme 2-43. Ni-catalyzed cross-coupling of enol triflates with Grignard reagents.

Other reactions described are those of imidazolides with Grignard reagents, which are carried out in the presence of the catalysts trimethylsilyl triflate, iron trichloride, or iron trisacetylacetonate ... 

Reactions of organomagnesium compounds with dialkyl sulfates or alkyl sulfonates often give satisfactory yields of the products of displacement of sulfate or sulfonate. Side-reactions have been observed, but they can often be avoided for example, an excess of the sulfate or sulfonate should be used with Grignard reagents, as some is consumed by nucleophilic attack by halide ion [A]. The dialkyl sulfates are reactive, but hazardous. Toluenesulfonates (tosylates) are less reactive, but their reactions are catalysed by copper complexes the reactions of trifluoromethanesulfonates (triflates) are catalysed by nickel complexes. Reactions of Grignard reagents with secondary tosylates appear to follow an Sn2 mechanism, with inversion of configuration [43],... 

In addition, amine N-oxides (82) can be treated with trialkylsilyl triflates to generate, after methyl-lithium treatment, a-siloxyamines (83) which, when allowed to react with Grignard reagents (or tiialkyl-aluminum), generate tertiary amines (M) in modest yields (Scheme 15). ... 

In the area of organometallic chemistry, we begin with a procedure for the palladium-catalyzed animation of aryl halides and aryl triflates, illustrated by syntheses of N-HEXYL-2-METHYL-4-METHOXYANIUNE and N-METHYL-N-<4-CHLOROPHENYL)-ANILINE. The next procedure describes the synthesis of 1,2,3,4-TETRAHYDROCARBAZOLE by the palladium-catalyzed annulation of ketones with o-iodoaniline. Next, a procedure for the synthesis of 2,7-DIMETHYLNAPHTHALENE via the nickel-catalyzed coupling of aryl O-carbamates with Grignard reagents is presented. The fourth procedure in this section describes the synthesis of 5-METHYL-2,2 -BIPYRIDINE by a Negishi cross-coupling reaction... 

N-t-Butyldimethylsilylpyridinium triflate (45) reacts with Grignard reagents with almost complete regiospecifity to afford the corresponding 1,4-dihydropyridine derivatives which are easily oxidised by oxygen to give 4-substituted pyridines (46). ... 

Silylation at nitrogen with t-butyldimethylsilyl triflate, generates pyridinium salts which, because of the size of the A -substitutent, react with Grignard reagents exclusively at C-4 montmorillonite-catalysed addition of silyl enol ethers to pyridines has a comparable effect in producing l-trimethylsilyl-l,4-dihydropyridines carrying an acylalkyl substituent at C-4. ... 

Recently the mesylate group was developed as an inexpensive alternative to the triflate group in Ni(0)-catalyzed homocoupling and cross-coupling reactions. Aryl mesylates participated in coupling reactions with Grignard reagents (97). 

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