CatalyticC-Alkylation of Secondary Amines with Alkenes

Titanium‐Catalyzed Hydroaminoalkylation of Ethylene

“…Then the obtained mixture was stirred at temperatures between 105 and 160 °C for 3–48 h and finally, the crude product mixture was purified by column chromatography. Consistent with the 1980′s experiments, it was first found that tetrakis(dimethylamino)titanium does not show any catalytic activity up to temperatures of 140 °C (Table , entry 1). On the other hand, [Ind 2 TiMe 2 ] (Ind=η 5 ‐indenyl) does catalyze the reaction at a temperature of 105 °C and delivers the expected hydroaminoalkylation product N ‐propylaniline ( 2 a ) in 69 % yield after a reaction time of 24 h (Table , entry 3).…”

Catalytic Hydroaminoalkylation

“…This kind of reaction, which includes CÀH bond activation at the a position to an amino group, [11] was first reported at the beginning of the 1980s, but was not further developed until recently. [12,13] The early work of Maspero and Clerici involved the intermolecular a alkylation of dimethylamine with terminal alkenes in the presence of [Zr(NMe 2 ) 4 ], [Nb(NMe 2 ) 5 ], and [Ta(NMe 2 ) 5 ].[12] Moderate yields (38 %) were obtained at 200 8C over 150 h. According to mechanistic studies reported later by Nugent et al, [13] an azametallacyclopropane was suggested as a key intermediate (Scheme 2). In a similar reaction, a-alkylated secondary amines were prepared in the presence of stoichiometric quantities of zirconocene methylamido complexes.…”

Theoretical Studies on the Hydroaminoalkylation of Alkenes with Primary and Secondary Amines

“…An existing problem with the further development of this very promising new synthetic method is the fact that for early transition‐metal catalysts, not a single example of an intermolecular hydroaminoalkylation of an alkene using a primary amine (Scheme , R 1 =H) is known to date, while secondary amines, including dimethylamine (Scheme , R 1 =Me, R 2 =H), react easily . From a preparative and industrial point of view, this limitation to the use of secondary amines is extremely regrettable, since especially the conversion of primary amines [for example, industrially important methylamine (Scheme , R 1 =R 2 =H)] would offer an immense synthetic benefit.…”