Amines rearrangement

A related amination/rearrangement/cyclization tandem sequence had been introduced by Cossy [49]. Starting from cyclic epoxyketones 224 the reaction with propargylamines 225 caused an oxirane-opening condensation process to generate the enaminoketones 226. Upon heating in toluene to reflux, aza-Claisen rearrangement delivered the intermediate allenyl imines 227, which... 

Fig. 5. Addition reaction products from hexahydrophthalic anhydride and diisopropanol-amine rearrangement from AB2 to ABB monomer...

Aminopenici11 anic acid (I) is acylated, oxidized and esterified to give the sulfoxide ester (II). Sulfoxide ester (II) is converted to its C-6 epimer (III) by treatment with trimethyl chiorosilane and triethyl amine. Rearrangement of III using triphenyl phosphine yields the epioxazoline (IV). 

The effect of substituents on C(2) of vinyl bromide and on the amine of the palladium catalyst in the. S n reaction with secondary amines was examined. The catalyst formed from the reaction of Pd2(dba)3 with proazaphosphatrane (12) gave the best yields (>91%) of enamine.16 The. S n product formed with primary amines rearranged to give the imine as the product in yields of >86%. 

Some l-alkyl-4-aryl-3-piperideines are obtained from a-methyl-styrene and its derivatives by the reaction with formaldehyde and hydrochloride of a primary amine, rearrangement of the resulting oxazine derivative (14) with sulfuric acid or hydrochloric acid to l-alkyl-4-aryl-4-piperidinol, and dehydration of the latter.13-15... 

The alkaloid (+)-pinidine81 (4) is obtained as a single a s-stereoisomer in a one-pot transformation of the chiral methyl sulfide 3 via oxidative amination, rearrangement, intramolecular imine formation and stereoselective reduction. 

Since 1980, the applications zeolites and molecular sieves in the speciality and fine chemicals increased enormously. Zeolites are being used in the various types of reactions like cyclization, amination, rearrangement, alkylation, acylations, ammoxidation, vapour and liquid phase oxidation reactions. Zeolites and molecular sieves have also been used to encapsulate catalytically active co-ordination complexes like ship-in-bottle and as a support for photocatalytic materials and chiral ligands. Redox molecular sieves have been developed as an important class of liquid and vapour phase oxidation and ammoxidation reactions. We have discussed few typical recent examples of various types of reactions. 

In the rearrangement of allyl fluoroacetates, trialkylsilyl triflates have been introduced as a new reagent for the Z-selective generation of silyl ketene acetals485. Thus, when (T)-crotyl fluoroacetates are treated at ambient temperatures with a trialkylsilyl triflate in the presence of a tertiary amine, rearranged products with a svn relationship are preferentially obtained. The ketene acetal intermediates cannot be isolated and the geometry has been deduced from the stereochemistry of the products. The selectivity of this process improves in the order triisopropyl > ferf-butyldimethylsilyl > rerf-hexyldimethylsilyl > trimethylsilyl a triethylsilyl (see Table 11). 

The derivatives 86 were isolated as purple solids in moderate )tield (50-60%) when the orf/zo-quinones 85 were generated under oxidative conditions. It should be noted that the corresponding tertiary amines rearrange to the tautomeric para-quinomethanes, which cydise forming pyrrolidinium salts (030BC3120). 

Conversion of coordinated N-(2-aminoethyl)ethylenimine occurs in a similar manner.55 The thiocyanate complex obtained in the first stage of the reaction undergoes a thiocyanogen-amine rearrangement. Scheme 11.12 ... 

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