N-alkylimines

Table 8. 1,2-Asymmetric Induction in the Addition of Organometallics to N-Alkylimines 4, Cram Selectivity 6...

V-Trimethylsilyloxymethylimines can be reduced to the corresponding N-alkylimines with Et3SiH/BF3-OEt2 (Eq. 320).522... 

Imines can be photoreduced by hydrogen donors such as propan-2-ol, but in some cases it is clear that a small amount of carbonyl compound (arising from hydrolysis of the inline) is necessary to initiate the process. For example, N-alkylimines of benzaldehyde give ethane-1,2-diamine derivatives on irradiation in 95% ethanol (5.6), but they are inert when irradiated in a perfectly dry alcohol. The C=N chromophore is capable of abstracting a hydrogen atom, and both the photoreduction of a tetrahydropyridine (5.7) and the photoaddition of p-xylene to an isoxazoline (5.8) occur by such a direct reaction. 

The [2+4] diastereoselective annulation of vinyl carbodiimides 48 to cyclic N-alkylimines 49 affords the S,S-diastereomer of the bicyclic dihydropyrimidine 50. This reaction is used in the synthesis of batzelladin alkaloids. 

Silylketene acetals react with imines under acidic conditions (Scheme 22). With N-alkylimines in the presence of a stoichiometric amount of TiCU, -lactams are formed in good yields. N-Aryl- " and N-trimethyl-silylimines also react under acidic conditions but yield only open-chain products. On the other hand, bis(trimethylsilyl)ketene acetals yield 3-lactams with both N-alkyl- and N-aryl-imines (Scheme 22). °... 

Relatively little is known about the E-Z isomerization of N-alkylimines (7a). The reversible photoisomerization of anils (7b), however, has been studied in some detail. Since the quantum yield of intersystem crossing 4>isc... 

Reaction Wave function Alkene, photocycloaddition, 366. 420-23 addition to benzene. 420 substituted, 432 Alkyl amines, tertiary. 466 Alkyl aryl ketones, 399, 402 Alkylethylenes, 420 Alkylidenecyclopropene. 57-58 N-Alkylimine, 375 Alkyl iodide, 471 Alkyl methyl ketones. 383-84 Alkyl radical, 380 Allene. 416 Ally radical. 102, 460 Allyl resonance, 461... 

The intramolecular cycloaddition of o-quinone methide N-alky1imines with alkenes to form six-membered nitrogen rings is well documented but the intermolecular reaction is less well characterised. Ito et al. have now shown that the o-quinone methide N-alkylimines (182), generated in situ by treatment of the corresponding N-trimethylsilyltrimethylammonium salts (181) with fluoride ion, react with the electron-deficient alkenes (183)... 

As already documented for other azoles, methods for transition metal-mediated approaches to imidazoles with different substitution pattern have been disclosed recently, (a) In the Pd-catalyzed multicomponent approach, N-alkylimines, acid chlorides and N-tosylimines are coupled in the presence of a phosphine, DIPEA/LiCl, carbon monoxide, and a specific Pd(0) catalyst to give tetrasubstituted N-alkylimidazoles 48 [398] ... 

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