Alkyl intermolecular hydroamination

Chang et al. reported a mild tandem intramolecular hydroamination of yne amines to form an endo-adduct intermediate, which reacts with electron-deficient azides to produce cyclic amidines <06JA12366>. Selected examples of an interesting synthetic route to tropene derivatives 165 via a dual hydroamination strategy is shown below. This one-step reaction makes use of a palladium catalyst and takes place by sequential intermolecular hydroamination of cycloheptatriene with aryl, heteroaryl, and primary alkyl amines to generate intermediate 166, followed by transannular intramolecular hydroamination <06JA8134>. 

In addition to C-alkylation reactions, hydroaminations are of great interest in organic synthesis [85, 86]. Recently, Shibasaki and coworkers developed a Bi(OTf)3-catalyzed intermolecular hydroamination using styrenes [87] and... 

The organoactinide complexes Cp 2AnR2 (An = Th, U R = Me, NHR R = alkyl) and the bridge complexes 3-6 were found to be excellent precatalysts for the intermolecular hydroamination of terminal aliphatic and aromatic alkynes in the presence of primary aliphatic amines to yield the corresponding imido compounds [56, 99]. The reactivity exhibited for the thorium complexes was different, depending on the alkynes, from that for organouranium complexes. 

The intermolecular process (8 and 9) showed two hydroamination regioselec-tivities depending on the precatalyst. The intermolecular hydroamination catalyzed by the metallocene thorium catalyst yielded the methyl alkyl-substituted imines in... 

Schafer found that the bulky bis(amidate) complex is an effective catalyst for intermolecular hydroamination of terminal alkyl alkynes with alkylamines, giving exclusively the anti-Markovnikov aldimine product [309]. The same titanium complexes can also be utilized in the hydroamination of substituted allenes in good yields (Scheme 14.132). Under the catalysis of an imidotitanium complex, the highly strained methylenecyclopropane can undergo hydroamination reaction with either aromatic or aliphatic amines, to give ring-opened imine products in good to excellent yields and chemoselectivities [310]. 

Alkylation. Alkylation of the title compound is also a key transformation to gain access to more elaborated triazoles. It has been shown that alkylation of the N-2 position using methyl iodide is possible by a Sn2 process (eq 3). Both N-1 and N-2 positions can be alkylated with no selectivity for either regioisomer. Various alkylating aromatic or aliphatic agents can be used and yields higher than 80% can be obtained. It is also possible to alkylate via a Mitsunobu reaction to afford a similar alkylation at the N-2 position (eq A)P It has also been shown that it is possible to alkylate both the N-1 and N-3 posihons to form nitrenium ions using an intermolecular hydroamination method (eq 5). ... 

The corresponding intermolecular addition of cyclic ureas to terminal alkenes is catalyzed by Au[P(/-Bu)2(o-biphenyl)]Cl and AgOTf, and it provided alkylated ureas in high yield at 100 °C. The reaction even works with ethylene and other gaseous olefins. In the presence of chiral gold(I) pre-catalyst [Au2 (S)-3,5-r-Bu-4-MeO-MeOBIPHEP Cl2] and silver triflate, the hydroamination products were obtained with 71-76% ee (Scheme 4-68). Treatment of cyclic ureas with allylic alcohols in the presence of cationic gold(I) catalysts afforded allylated ureas with... 

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