Palladium catalyzed intermolecular hydroamination of 1-substituted allenes: an atom-economical method for the synthesis of N-allylamines

Cationic [(Iminophosphine)Nickel(Allyl)]+ Complexes as the First Example of Nickel Catalysts for Direct Hydroamination of Allenes

“…Secondary amines functioned well in this system, forming linear allylamine products in moderate to good yields. The production of linear products was not surprising, as this is the thermodynamically favored product in these reactions . Primary amines of various types were invariably found to be unreactive, as observed in many cases with our less reactive Pd analogues …”

Enantioselective Intermolecular Addition of Aliphatic Amines to Acyclic Dienes with a Pd–PHOX Catalyst

“…Dong and co-workers demonstrated a Rh-catalyzed 1,2-hydroamination of unsymmetrical acyclic dienes utilizing indoline nucleophiles; in this case, an acid additive positively impacts enantioselectivity . Recently, the Hou lab disclosed the first highly enantioselective intermolecular hydroaminations with aliphatic amines, where chiral lanthanide half-sandwich catalysts allow for stereoselective amine additions to cyclopropenes. − In this work, we report the enantioselective 1,2-addition of alkyl amines to unsymmetrical acyclic dienes − catalyzed by a cationic Pd–PHOX complex . Transformations afford allylic amines in up to 91% yield in 3–24 h without added Brønsted acid.…”

“…We then turned our attention to phosphinooxazoline (PHOX) ligands, which have enjoyed a great deal of success in enantioselective allylic substitution, but to the best of our knowledge have not been employed in hydrofunctionalization reactions . We began by examining the Ph-substituted PHOX ligand L1 (Table , entry 1).…”

New Strategies for the Transition-Metal Catalyzed Synthesis of Aliphatic Amines

“…Although the intermolecular hydroamination of allenes has been known since 1976, Yamamoto reported the first general strategy in 1997 using Pd catalysis . Despite intensive efforts by Schmidt, bespoke Pd II catalysts are required in order to achieve high selectivities. − Although Yamamoto , and Widenhoefer , have accomplished significant work using Au catalysis, an elegant report by Breit described the first asymmetric intermolecular hydroamination of allenes 48 with anilines 49 using a Rh I /Josiphos catalyst in excellent yields and high enantioselectivities (up to 90% ee) (Scheme ). Mechanistic studies suggest that oxidative addition of the aniline affords a Rh III –H, which following hydrometalation of the allene to form the π-allyl–Rh complex, undergoes reductive elimination to afford the allylic amine 50 .…”