Alkenes aminomethylation

Increasing the hydrogen partial pressure enables a subsequent enam-ine/immonium hydrogenation and thus leads to an n-regioselective hydro aminomethylation of terminal alkenes. In this case the optimal results were obtained with the rhodium(I)/XANTPHOS catalyst (Scheme 14) [59]. 

In a similar manner, polymers with unsaturated chains or side chains can be converted to polyamines [66-69]. Conjugated diolefins usually undergo hydroformylation with low selectivities [70]. Mostly hydrogenation of at least one double bond occurs and mixtures of various saturated and unsaturated amines and diamines are obtained [71]. Similar to alkenes also alkynes may serve as unsaturated compounds in hydro aminomethylation reaction sequences. Although synthetically attractive, only a few investigations towards hydroformylation and hydroaminomethylation of alkynes in the presence of N-nuclcophilcs are known. Usually a preferred transformation to furanonic derivatives is observed under hydroformylation conditions [27]. 

The application of various ruthenium compounds in acetonitrile330 or rhodium and ruthenium catalysts or their mixtures331 was found to show significant improvements (high product selectivities, high linearities) in the aminomethylation of terminal alkenes to produce tertiary amines. 

Work in the reactions of alkyl halides with the more conventional Gilman cuprates has slackened considerably. Synthetically, alkylations have been performed employing alkynes as the second, disposable ligand in cuprates. In the transfer of vinyl groups, this allows aminomethylation or thiomethylation without the addition of HMPA or triethyl phosphite and without loss of alkene geometric integrity (equation 10)14. The addition of pentynylcopper to a-lithiated formamidines allows alkylation with primary alkyl iodides (equation ll)15. 

Except in a few cases,cyclic Mannich ba.scs derived from alkenes arc produced by the reaction of unsaturated amino derivatives with formaldehyde. Intramolecular aminomethylation (Fig. 65) takes place with aminoalkenes (184, X = H path a) or with analogous silyl allyl derivatives (184, X = SiMc , path b) ... 

Aminomcthylation of hctcroatoms (X-aminomcthylation in Table 6) is generally the easiest, whereas C-aminomethylation requires a great variety of experimental conditions. Indeed, the C—H moiety bound to a carboxyl group is among the less reactive systems, so that alkyl ketones require conditions A alkyl esters, which would be unstable under such conditions, have to be allowed to react with methyleneimmonium salts. Alkenes, as well as ferrocenyl derivatives, are also barely reactive. By contrast, the nitro group of nitroalkanes behaves as a very good activator of aminomcthylation, and phenols are readily aminomethylated. 

Aminomethylation of alkenes affords a quite large range of products, the aminomethylated ones being reported in Fig. 62, as substantial amounts of nonbasic materials are also formed. Alkenes used as substrates (Table 11) are usually allowed to react with dimethylamine other amines - - tend to complicate the reaction further. Cyclic... 

Terpenoids are subjected to aminomethylation in order to intrtxiuce a basic moiety into the molecule. The reactive site of the substrate is usually an alkene or alkyl ketone group however, unsaturated derivatives of type 490 arc obtained from terpenes suitably functionalized by the alkyne moiety. ... 

Due to the rather complex structure of terpenoid sub-strate.s, chemo- and regio.selcctivity of the reaction as well as the possibility of rearrangements in the substrate moiety are to be taken into account. Indeed, the widely invest -gated aminomethylation of alkene derivatives indicates that... 

Alkene isomerization Alkene hydrogenation Ketone hydrogenation Hydrogenation of cyanides Hydrogenation of nitro group Alkyne hydrogenation Aminomethylation Water gas shift reaction... 

Hydrozirconation of phospha-alkenes has given the three-membered ring system (163). Addition of dicyclohexyl-borane to the phospha-alkene PhP=CHNMe2 results in the dimeric system (164), and in its reaction with an ethylsiloxane reagent, this phospha-alkene gives a mixture of aminomethyl-... 

Aminomethylation of alkenes. The original procedure of Reppe for aminomethyla-tion of alkenes (equation 1) employed iron pentacarbonyl, Fe(CO)5 (1,519-520 2,229 230 3, 167), as catalyst. Iqbal2 now finds that rhodium oxide is a far more effective... 

In the presence of a nickel(II) catalyst, suUamates can be used as nitrogen sources for the intramolecular vicinal diamination of alkenes 141 (Scheme 16.37). While the mechanism of this oxidative transformation is not fully understood, the reaction bears the advantage that cyclic sulfamates 142 undergo selective deprotection under conventional conditions. Hence, this diamination protocol represents an attractive approach to free aminomethyl pyrrolidines (100). 

Aminomethylation of olefins can be attained in good yields by reaction of alkenes with secondary amines, carbon monoxide, and water in the presence of Rh203 and/or Fe(CO)5. Rhodium oxide is superior to Fe(CO)5 but highest yields can be realized when they are used together. This reaction has been applied to the synthesis of long-chain alkylamines (Iqbal, 1975). 

Thiobenzamide has been reported to undergo a Mannich-type reaction on simultaneous treatment with aldehydes and arylsulphinic acids, yielding the compounds (267). 2-, 3-, and 4-thiocarbamoylpyridines similarly gave the N-(aminomethyl)thioamides (268) by reaction with a variety of amines in the presence of formaldehyde. A new stereospecific synthesis of 5,6-di-hydro-4H-l,3-thiazines (269) depends on the reaction of thioamides with aldehydes and alkenes it was considered likely that (270) is an intermediate in this reaction. 

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