Allylic amines, trisubstituted

Scheme 5 Enantioselective iridium-catalyzed hydrogenation of alkynes in the presence of N-arylsulfonyl imines to furnish trisubstituted allylic amines...

Scheme 9 that both the molybdenum and iron complexes can catalyze the allylic amination of nonfunctionalized alkenes with an ene-like transposition of the double bond, but also that the yield of the allyl amine formed, 113, is moderate to high. It is generally found that higher substituted alkenes tend to give the best yields, and un-symmetrical alkenes (trisubstituted) react with virtually complete regioselectivity, as only one isomer is detected. The byproducts are primarily azoxybenzene and aniline, which arise from condensation of nitrosobenzene with phenyl hydroxylamine and reduction of phenyl hydroxylamine, respectively. 

Primary allylic amines. Aziridines can be converted into allyl carbamates by reaction with ethyl chloroformate to form N-ethoxycarbonylaziridines followed by thermolysis in benzene at 200-250°, Rearrangement of trisubstituted ethoxycarbonylaziridines is regiospecific. 

The stereospecific olefination method involving synthesis, separation, and base-catalysed, decomposition of diastereomeric P-hydroxyalkylphosphine oxides has been used for the preparation of pure isomers of y,S-unsaturated acetals (Scheme 11). The same principle has been extended to trisubstituted alkenes. The yields are generally still good, but the diastereomeric hydroxyphosphine oxides involved are less stable in some cases and the routes to them are less stereoselective. However, the method works reasonably well for the synthesis of ( )-and (Z)-allylic amines (Scheme 12). Unfortunately, (2-substituted-2-amino)-... 

Similar isomerisation reactions have been apphed to other substrates with very high enantioselectivities for many trisubstituted allylic amines. In general, the rearrangement of allylic alcoholsand ethers provides lower enantioselectivity. However, higher ees have been obtained in the isomerisation of cyclic acetals and the desymmetrisation of 4,7-dihydro-1,3-dioxepins such as (12.06) occurs with up to 92% ee in the presence of the nickel-DUPHOS catalyst (12.07). Unfunction-alised alkenes have been isomerised enantioselectively using a titanocene catalyst. ... 

The Pauson Khand reaction is compatible with a wide variety of functionalities, such as ethers, alcohols, tertiary amines, thioethers, ketones, ketals, esters, tertiary amides, carbamates, and benzene, furan, and thiophen rings. Disubstituted alkynes, alkenes with bulky allylic substituents, and trisubstituted alkenes frequently afford reduced yields of products. Because of the reduced ability of sterically hindered alkenes to coordinate and undergo insertion, insertion of one or more molecules of alkyne occurs instead. 

A preparative method for allylamines is based on the Pd-catalyzed substitution reaction of /V-allylbenzotriazoles by amines. Formic acid is a convenient hydride source for allylic deoxygenation of Baylis-Hillman adducts via their derived acetates, thus the reaction is the conclusion of a three-step process for access to trisubstituted alkenes which contain one electron-deficient group. 

Subsequently, a one-pot three-component highly stereoselective synthesis of hitherto unknown trisubstituted ( )- and (Z)-allyl dithiocarbamates 831 and 832 in water at room temperature without using a catalyst was disclosed (Scheme 4.241). This one-pot procedure was performed simply by stirring a mixture of an amine, CS2, and an acetate of acrylonitrile/acrylate ester-derived MBH adduct in water at room temperature for 6-10 h to afford the corresponding allyl dithiocarbamates 831 and 832 in 83-94% yields along with... 

In 1919, Meisenheimer reported a detailed account of an unusual transformation of methyl-allyl-aniline 3 in the presence of benzoic peracid 4, which yielded the N,N,0-trisubstituted hydroxylamine product 6 through amine iV-oxide 5 tScheme IS.21. Although the mechanism of the process was not fully appreciated at the time, this discovery was one of the earliest examples of a [2,3]-sigmatropic rearrangement, and it served as the foundation for the discovery and development of many [2,3]-rearrangements of reactive zwitterionic substrates. 

Enhancing the utility of the allq lation-rearrangenient sequence in synthesis, the Evans group addressed the problems of a-versus-y alkylation as well as low anion reactivity by employing heterocyclic sulfides as the alleviation substrates tScheme IR.IfiE For instance, allylic imidazolyl sulfide 56 could be allqvlated efficiently, reaction at the a-position being favored by a chelated but reactive allyl lithium intermediate. Oxidation of 57 to the allylic sulfoxide and treatment with a secondary amine thiophile provided allylic alcohol 58 in high yield and with excellent stereoselectivity at the trisubstituted alkene. Allylic oxidation with manganese dioxide completed a synthesis of the sesquiterpene nuciferal (59). ... 

Formation of O, N, A -trisubstituted hydroxylamines from tertiary amine oxides via [1,2]-R group migration, or [2,3]-sigmatropic rearrangement when R = allyl ... 

Pyrolysis of 5-ethyl iV-disubstituted dithiocarbamates gives ethylene, CS2, and secondary amines and/or a trisubstituted thiourea and ethanethiol. NNSS -Tetrasubstituted dithiocarbamidium iodides, obtained by 5-alkylating dithiocarbamates, are in equilibrium with their precursors, and this equilibrium has been used in the conversion of allylic dithiocarbamates, particularly allylic 1-pyrrolidine-carbodithioates (147), into allylic iodides by treatment with methyl iodide bis(methylthio)methylenepyrrolidinium iodide (148) is insoluble, and it precipitates from the reaction mixture (Scheme 15). AW55 -Tetramethyldithiocarbamidium iodide (149) reacts with hydroxylamine or semicarbazide with displacement of the dimethylamino-group, but with other nucleophiles, e.g. thiosemicarbazide or... 

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