Imines with organometallic

Reaction of Nitriles with Organometallic Reagents Grignard reagents add to a nitrile to give an intermediate imine anion that is hydrolyzed by addition of water to yield a ketone. 

Fluoral hydrate and hemiacetals are industrial products. They are stable liquids that are easy to handle, and they react as fluoral itself in many reactions. Thus, in the presence of Lewis acids, they react in Friedel-Crafts reactions. They also react very well with organometallics (indium and zinc derivatives) and with silyl enol ethers.Proline-catalyzed direct asymmetric aldol reaction of fluoral ethyl hemiac-etal with ketones produced jS-hydroxy-jS-trifluoromethylated ketones with good to excellent diastereo- (up to 96% de) and enantioselectivities. With imine reagents, the reaction proceeds without Lewis acid activation. The use of chiral imines affords the corresponding 8-hydroxy ketones with a 60-80% de (Figure 2.49). ° ... 

One of the most studied imine precursors in the reaction with organometallic compounds is (3R,4R)-4-acetoxy-3-[(R)-l -((t-butyldimethylsilyl)oxy)ethyl]-2-azetidinone (31) (equation 23)97. 

Although the diastereoselective addition of nucleophiles to imines offers an attractive route to chiral amine derivatives, most chiral nonracemic imines suffer from low reactivity (electrophilicity), resulting in no reaction or competitive reduction with organometallic reagents. Other problems include enolization of aliphatic imines, poor... 

Imines with an adjacent chiral auxiliary undergo diastereoselective addition of organometallic reagents in a similar fashion, as discussed above (equation 122)487. The products are readily converted into enantiomeric /J-amino alcohols, which are useful in further synthetic sequences or the target moiety in some natural products. Other such syntheses have been performed via additions to both imines488-490 and the related hydrazone moiety491-493. 

See also reduction of imines with diethylzinc under Addition of Organometallics above, and ionic hydrogenation of Iminium Species below. 

Enediamine 93 undergoes an easy C-alkylation with a,/ -unsaturated ketones under comparable conditions and no cyclocondensation products are observed36. Similar C-alkylations with other electrophilic olefins such as unsaturated lactones, propenonitrile, vinyl sulfoxide, sulfone and phenylphosphonium bromide have been achieved36. All the adducts 135 exist predominantly as the imine form (see Section II.A). Treatment with organometallic reagents transforms the C-alkylated products into... 

Aqueous organometallic catalysis allows the use of NH3-solutions in water for the direct synthesis of amines from olefins in a combined hydroformylation/reductive animation procedure (Scheme 4.19). The hydroformylation step was catalyzed by the proven Rh/TPPTS or Rh/BINAS (44) catalysts, while the iridium complexes formed from the same phosphine ligands and [ IrCl(COD) 2] were found suitable for the hydrogenation of the intermediate imines. With sufficiently high NHs/olefin ratios (8/1) high selectivity towards the formation of primary amines (up to 90 %) could be achieved, while in an excess of olefin the corresponding... 

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