Alkene Hydroxy amination

Alkene Amine Time Reducing //-Hydroxy Amine b d.r. Yield Ref... 

Z)-Disubstituted and trisubstituted alkenes were considerably less reactive. For example, cyclohexene does not react with the triimido complex and afforded only the hydroxy amine in poor yield with the diimido complex. 

The reaction of aryl azides with excess alkenes in the presence of trifluoroacetic acid proceeds by an analogous mechanism and afforded, after basic hydrolysis, /5-hydroxy amines together with byproducts. A diastereoselective reaction was observed only with cyclic and acyclic (Z/-alkenes, e.g., 12 and 1388. From methyl ( )-2-butenoate, A-phenylthreonine methyl ester was similarly prepared in 30% yield88. 

An alkene activated by an electron-withdrawing group—often an acrylic ester 2 is used—can react with an aldehyde or ketone 1 in the presence of catalytic amounts of a tertiary amine, to yield an a-hydroxyalkylated product. This reaction, known as the Baylis-Hillman reaction, leads to the formation of useful multifunctional products, e.g. o -methylene-/3-hydroxy carbonyl compounds 3 with a chiral carbon center and various options for consecutive reactions. 

Anodic regioselective acetamidosulfeny-lation of alkenes is similarly achieved by oxidation of diphenyldisulfide in acetonitrile [81]. Cyclic enamines, which are intermediates in the oxidation of cyclic N-methoxycarbonyl amines, react in aqueous acetonitrile that contains chloride ions to a-hydroxy- 8-chloro compounds via intermediate chloronium ions [82]. Enolethers undergo a regioselective azidomethoxyla-tion to yield acetals of a-azido carbonyl compounds upon electrolysis in methanol containing sodium azide [83]. The reaction proceeds possibly via addition of an anodicaUy generated azide radical. 

The diastereoselectivity in the ene reaction of O2 with chiral alkenes bearing a stereogenic centre at the a-position with respect to the double bond has been extensively studied. Chiral alkenes which bear a substituent on the asymmetric carbon atom other than the hydroxy or amine functionality afford predominately erythro allylic hydroperoxides. The erythro selectivity was attributed to steric and electronic repulsions between... 

As stated above, aliphatic amines are potent ligands for electrophilic transition metals and are efficient catalyst poisons in attempted alkene animation reactions. However, tosylation of the basic amino group greatly reduces its complexing ability, yet does not compromise its ability to nucleophilically attack complexed alkenes. Thus, a variety of alkenic tosamides efficiently cyclized under palladium(II) catalysis producing N-tosylenamines in excellent yield (equations 17 and 18).32 Again, this alkene amination proceeded through an unstable a-alkylpalladium(II) species, which could be intercepted by carbon monoxide, to result in an overall aminocarbonylation of alkenes. With ureas of 3-hydroxy-4-pentenyl-amines (Scheme 7), this palladium-catalyzed process was quite efficient but it was somewhat less so with... 

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