Asymmetrische intermolekulare Hydroaminierung nichtaktivierter Alkene mit einfachen Aminen

Abstract

Eine harte Nuss zu knacken: Die asymmetrische intermolekulare Markownikow‐Addition einfacher Amine an nichtaktivierte Alkene gelingt mithilfe von Binaphtholat‐Seltenerdmetallkatalysatoren mit bis zu 61 % ee und 73 % de, wenn R2 ein stereogenes Zentrum enthält.

Enabling Bifunctionality and Hemilability of N‐Heteroaryl NHC Complexes

“…Intriguingly, congener 5 c ‐Rh (entry 5) gives isomerization exclusively as quickly as 5 c performs selective hydroamination, showing a dramatic role for the central metal in the course of the cyclization. Although our preliminary results have not resulted in a hydroamination catalyst significantly more active than recent impressive improvements in the state‐of‐the‐art,11a–e,q nonetheless the fact that a completely inactive NHC‐based system ( 5 a ) can be turned into a synthetically useful one constitutes a significant proof of concept. We also note that the consumption of the secondary amine substrate 18 b is at least 20 times faster than that of the primary amine (entry 4 versus entry 3), affording cyclized product in higher yield (89 %) using 5 c , which are differences consistent with results from other known rhodium and iridium based catalysts 11b,i.…”

Enantioselective Rhodium‐Catalyzed Synthesis of Branched Allylic Amines by Intermolecular Hydroamination of Terminal Allenes

“…[4] Despite extensive effort, efficient methods for catalytic enantioselective intermolecular hydroamination are rare. [5] Although the enantioselective intermolecular hydroamination of allenes would be an efficient method for the synthesis of a-chiral allylic amines, [6,7] only one example has been reported, which requires internal allenes, has a limited scope, and provides only moderate levels of enantioselectivity (Scheme 1 a). [8,9] To date, the enantioselective intermolecular hydroamination of mono-substituted allenes has not been reported, owing to the propensity of many hydroamination catalysts to form achiral products (either imines or linear allylic amines) from such substrates (Scheme 1 b).…”

CN and CC Bond Formations in the Thermal Reactions of “Bare” Ni(NH2)+with C2H4: Mechanistic Insight on the Metal‐Mediated Hydroamination of an Unactivated Olefin

“…[9] Notwithstanding all progress, the intermolecular hydroamination of unactivated olefins using simple amines remains quite challenging. [10] However, a metal-free hydroamination of ethylene by ammonia was recently observed using an electron beam impinging on C 2 H 4 /NH 3 multilayer films. [11] Quite clearly, for the development of efficient catalysts, knowledge of the elementary steps of a cycle as well as insight in the intrinsic properties of the active catalytic centers are indicated.…”