Nitrogen nucleophiles alkenes

A Cu(OAc)2-catalyzed intramolecular diamination of alkenes using sulfamide substrates such as compound 214 provides a route to fused thiadiazolidines 215 (Equation 48) <2005JA11250>. In this reaction, the transition metal activates the alkene toward nucleophilic attack by the first nitrogen, then becomes displaced by the second nitrogen nucleophile (a net M +z to M reduction). 

Palladium-catalyzed reactions of alkenes containing nitrogen nucleophiles have proven to be a powerful methodology for C—N bond formation leading to pyrroles. 

The advantage of the nitro group as radical precursor is best seen in the context of intramolecular nucleophilic trapping of alkene radical cations by nitrogen nucleophiles, when no cyclization was observed prior to treatment... 

Figure 15.7. Palladium catalysed addition of nitrogen nucleophiles to alkenes...

An alternative route from alkenes to 2-azasulfides reported by the groups of Caserio and Trost involves addition of a thiosulfonium salt, e.g. dimethyl(methylthio)sulfonium tetrafluoroborate (MeSS-Me2+ BF4-), followed by treatment of the resultant thiosulfenylated adduct with an amine or other nitrogen nucleophiles (Schemes 2320 and 24).35 Trost reports that the addition of the thiosulfonium salt can be followed by addition of an oxygen nucleophile, such as acetate, or a carbon nucleophile, such as cyanide, effecting oxosulfenylation and cyanosulfenylation, respectively (Scheme 25).36... 

Cyclizations with nitrogen nucleophiles involving alkynes and allenes have received little attention until recently. The cyclizations of several a-aminoallenes to 3-pyrrolines with silver tetrafluoroborate was reported by Claesson and coworkers (equation 133).264 A similar cyclization to form A -carba-penems has been reported (equation 134).265 Diastereomeric allenes (R1 R2) were shown to cyclize with complete stereocontrol. Cyclization with palladium chloride in the presence of allyl bromide or electrophilic alkenes allowed for the intermediate vinylpalladium species to be trapped by the electrophile.2651 A related product was obtained by cyclization of an alkynic substrate (equation 13S).265 Other examples of 5-endo cyclization of p-aminoalkynes50 include the formation of indoles by cyclization of 2-alkynylanilines with mercury salts200 or palladium chloride,266a,266b,266c formation of 1-pyrrolines with catalytic palladium chloride (equation 136)198 and formation of pyrroles by cyclization of hydroxy-substituted p-aminoalkynes.198,2666... 

Nitrogen nucleophiles such as amines (and in intramolecular cases, amides and tosamides) readily add to alkenes complexed to palladium(ll) and iron(ll) with reactivity and regiochemical features parallel to those observed for oxygen nucleophiles. However, these metal-assisted animation reactions are subject... 

Cationic cyclopentadienyliron dicarbonyl (Fp) alkene complexes are generally reactive towards a wide variety of nucleophiles, including nitrogen nucleophiles, but they too generate stable chemical step (usually oxidation). This makes catalysis impossible and severely limits application of this methodology to organic synthesis (equation 21 ).36 However, in contrast to palladium, iron is relatively inexpensive and stoichiometric procedures... 

Azasulfenylation of alkenesf s The adducts of dimethyl(methylthio)-sulfonium tetrafluoroborate (1) with alkenes react slowly but smoothly with various nitrogen nucleophiles to give products of overall rrarw-addition to the alkene. Regioselectivity depends on the substitution pattern of the alkene and on the nucleophilicity of the attacking reagent, and is subject to some control. The mechanism of this azasulfenylation is not certain it may involve an episulfonium ion. 

Fluorinated -alkenes and -cycloalkenes have a special relationship with their hydrocarbon analogues, usually exhibiting a chemistry that is complementary. For example, the fluorinated systems are frequently susceptible to nucleophilic attack, in some cases dramatically so, and therefore reactions of nucleophiles with fluorinated alkenes often reveal unique new chemistry. This chapter covers electrochemical reduction, principles governing orientation and reactivity of fluorinated alkenes towards nucleophiles, fluoride ion as a nucleophile and the mirror-image relationship of this chemistry with that of proton-induced reactions, reactions with nitrogen-, oxygen-, carbon- centred nucleophiles etc., and, finally, chemistry of some oligomers of fluorinated -alkenes and -cycloalkenes. 

Addition of Hydrogen Halides to an Alkene Section 11.2 Addition of a Nitrogen Nucleophile to an Aldehyde or a Ketone Section 18.8 Figure 18.3 Addition of Phosphorus Ylides to an Aldehyde or a Ketone (The Wittig Reaction) Section 18.7 Figure 18.2... 

But due to the importance of nitrogen functional groups, the addition reactions of selenium electrophiles to alkenes using nitrogen nucleophiles represent another synthetically relevant process. Nitriles have been used as versatile... 

As a rule, in nucleophilic additions to halogenated alkenes, the nucleophile always becomes attached to that carbon of the double bond that has lower electron density. In this case, back-donation of electrons by fluorine is stronger in the difluoromethylene group, and nitrogen therefore attacks the difluoromethylene group while proton adds to the other carbon. Because of the basicity of the reaction mixture, hydrogen fluoride is eliminated, and an imide fluoride, 3-chloro-2,3-difluoro-l-phenyl-1-aza-propene is formed ... 

In addition to the most important 1,2-difunctionalization assisted or catalyzed by palladium(II) complexes, a catalytic 1,1-arylamination process of alkenes, applied to the construction of nitrogen heterocycles from 4-pentenylamides, was realized29,30. The mechanism involves the formation of arylpalladium chloride from alkyl(aryl)stannanes, the addition to the alkene, the isomerization of the adduct to the more stable benzylic palladium complex, and the displacement of palladium by an internal nitrogen nucleophile. In the presence of a substituent, mixtures of diastereomers were generally obtained. 

One of the most important addition reactions which involves nitrogen nucleophiles is the azidoselenenylation of alkenes because both the azido and the phenylseleno group can give rise to several useful transformations. These compounds were first prepared by Krief from the reaction of alkenes with PhSeBr followed by sodium azide in DMF [54]. Direct azidoselenenylation of alkenes can be effected with PhSeCl and sodium azide in DMSO [55]. Under these conditions the reaction is stereospecific but it is not regiospecific. Similarly, the reaction of exocyclic alkenes with N-(phenylseleno)phthalimide and azido-trimethylsilane in methylene chloride (Scheme 11) gives rise to a 1 1 mixture of the regioisomers 67 and 68 [56]. 

Opening the epoxide with a nitrogen nucleophile makes one isomer. At least the alkene is symmetrical so it doesn t matter which end of the epoxide is attacked by the nucleophile. We have chosen azide ion (N ) as the nucleophile. Ammonia wdll also do as, although it can react repeatedly, it usually behaves itself with epoxides. You were not asked to make both diastereoisomers, so we can stop there. 

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