Grignard reagents reaction with iminium salts

Reaction of Grignard Reagents with Iminium Salts... 

The reaction has been extended to the preparation of ketones 1542 treatment of a dihydro-1, 3-oxazine (133) with methyl iodide forms the iminium salt 134 (0-43) which, when treated with a Grignard reagent or organolithium compound (6-35), produces 135 which can be... 

The allylation of imines with allylindium reagents in organic solvents gives the corresponding homoallylic amines.251-253 Under solvent-free conditions, the indium-mediated reaction of iV-benzylideneaniline furnishes a mixture of mono-allylated 79 and bis-allylated products 80 (Equation (56)). The bis-allylated product 80 presumably arises via a formation of an iminium salt, which is subsequently attacked by the allylindium nucleophiles. Formation of 80 is entirely suppressed by addition of allyl bromide to indium metal prior to any addition of the imine (Grignard-type reaction).254... 

Both the silyl derivative (59) and the alcohol (60) may be used as sources of the iminium salt (61) in reactions with a wide variety of nucleophiles. In practice, it was found feasible to use Grignard reagents for reaction with the silyl derivative, while TiC was effective in promoting attack on the carbinol amine by weaker nucleophiles. The process is shown in Scheme 24 using the addition of indole as an example. 

E)-l-Chloro-3-(N,N-dimethylamino)-1-arylprop-l-enes are conveniently prepared from aryl chloropropeniminium salts by reduction with sodium cyanoborohydride.75 Those iminium salts also undergo 1,2-addition of Grignard reagents (Scheme 32). N,N-Dialkylaminomethyl arenes can be obtained by the reaction of... 

C.iii. Reaction with Nitriles. Nitriles are carboxylic acid derivatives and react with Grignard reagents (also sec, 8.2.C).l Initial attack generates an intermediate iminium salt that can be hydrolyzed (with loss of ammonia) to the corresponding ketone. HO The best yields are obtained with aryl nitriles, and this is illustrated... 

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