Allyl vinyl amines

The rearrangement of unsymmetrical allylamines 9 was investigated to exclude any competing 1,3-rearrangement during the course of the reaction. Allyl vinyl amines 10 were generated via condensation starting from allylamine 9 and isobutyraldehyde 2. The substrates 10 were subjected to the acid-accel-... 

A third alternative may also be conceived, if for a moment one disregards all the nonparticipant atoms in compound IV. What is left is just an allyl-vinyl amine, a molecular combination reminiscent of what is necessary to perform a Claisen-type rearrangement (see Problem 19). Application of this rationale to intermediate IV would lead to cis structure III in a smooth, concerted fashion. This transformation is known in the literature as the amino-Claisen rearrange-... 

Examples of the aza-Claisen rearrangement of allyl vinyl amines and the thia-Claisen rearrangement of allyl vinyl sulfides have been reported. An efficient Lewis acid-catalysed Claisen rearrangement of zwitterionic A-acyl allylic amines... 

N-allyl/N-vinyl anilines were characterized by a rearrangement of the ahphatic moiety. The aromatic system had not been touched during the course of the process (Winterfeldt quinolone synthesis [15c]). The rearrangement of a NH allyl vinyl amine failed [15dj. 

Scheme 12.68 Ir-catalyzed allylic vinylation and allylic vinylation/amination domino reaction [161, 162],...

Addition to linear 1,1-disubstituted allylic acetates is slower than addition to monosubstituted allylic esters. Additions to allylic trifluoroacetates or phosphates are faster than additions to allylic carbonates or acetates, and reactions of branched allylic esters are faster than additions to linear allylic esters. Aryl-, vinyl, alkynyl, and alkyl-substituted allylic esters readily undergo allylic substitution. Amines and stabilized enolates both react with these electrophiles in the presence of the catalyst generated from an iridium precursor and triphenylphosphite. 

The Pd-catalyzed reaction of 5-vinyl-l,3-oxazolidin-2-ones 260 at 65-70°C and 65 atm of CO in ethanol gave 5-lactams 263 in fairly good to high yields (Scheme 38).As Scheme 38 illustrates, this decarboxylative carbonylation reaction is likely to involve (i) the cleavage of the allylic C-O bond of 260 to form tr-allyl-Pd complex syn-2(A, (ii) isomerization to anti-2(A, (iii) decarboxylation forming 7r-allyl-Pd-amine complex 262, and (iv) CO insertion to 262 followed by aminolysis to yield 5-lactam 263. 

While secondary alcohols are now relatively easy to prepare in enantiomerically-pure form, secondary amines have been more challenging. Larry Overman of UC Irvine reports (J. Am. Chem. Soc. 125 12412, 2003) the catalytic rearrangement of primary allylic alcohols such as 4 to the corresponding protected vinyl amine 5 with excellent . Hydrolysis of the amine 5 gives the GABA aminotransaminase inhibitor 6. Unnatural amino acids can be prepared by oxidative cleavage of the protected vinyl amines. 

Bismaleimides are produced by the condensation reaction of a diamine, such as methylenedianiline, with maleic anhydride. The reaction product tends to be crystalline with a high melting point. Eutectic blends of different bismaleimides reduce the melting point. However, a coreactant generally is required to improve the processing properties of the material. Bismaleimides owe their reactivity to the double bonds on each end of the molecule, which can react with themselves or with other compounds containing functional groups (vinyls, allyls. or amines). A typical bismaleimide structure is shown by ... 

Lithiation of vinylamines. The vinylic amine 1 is lithiated by f-BuLi at the tertiary vinyl position, presumably because of chelation with the dimethylamino group (equation I).1 Various allylic and methylallylic amines also can undergo... 

Asymmetric selenoxide elimination of the optically active vinyl selenoxides affords optically active allenes and cyclohexylidenes. On the other hand, asymmetric [2,3]sigmatropic rearrangement of allylic selenoxides, selenimides, and selenium ylides leads to the formation of the corresponding optically active allylic alcohols, amines, and homoallylic selenides, respectively. 

Allyl- (25) and phenacyl-amines (26) are also practical alternatives. They can be cleaved after isomerization of the allyl moiety to the acid sensitive vinyl amines, or with zinc in acetic acid. The bulky tri-phenylmethyl (Tr) group (27), readily removed by mild acid hydrolysis, possesses advantageous shielding properties and has found applications in the protection of amino acids (Scheme 16). ... 

Not only allyl, vinylic, and aryltins, but also alkyl and some hetero-substituted tins can be utilized in this protocol. Cyanomethylation, acetonylation, ethoxycarbonyl-methylation, and A, A -diethylamination required tri(o-tolyl)phosphine as ligand on palladium. Quite recently, aromatic amination was developed without the use of stannylamines.f ... 

---