The photoexcited state lifetimes of iron complexes are typically much shorter than those of iridium and ruthenium complexes. For that reason, iron complexes find less application in photochemical organic synthesis. Through iron photocatalysis, a mild and effective protocol for decarboxylative C-C and [a]

A concise deracemization of racemic secondary and tertiary amines with a tetrahydroisoquinoline core has been successfully realized by orchestrating a redox process consisted of N-bromosuccinimide oxidation and iridum-catalyzed asymmetric hydrogenation. This compatible redox combination enables one-pot, single-operation deracemization to generate chiral 1-substituted 1,2,3,4-tetrahydroisoquinolines with up to 98% ee in 93% yield, offering a simple and scalable synthetic technique for chiral amines directly from racemic starting materials.

Aryl boronic acids can be monofluoromethylated under nickel catalysis. The utility of this method is demonstrated by the monofluoromethylation of a borylated and acyl-protected derivative of the statin drug ezetimibe. Mechanistic investigations indicate that a fluoromethyl radical is involved in the Ni(I)/Ni(III) catalytic cycle.

A chiral phosphoric acid catalyzed asymmetric transfer hydrogenation of aromatic amines, quinolin-3-amines, was successfully developed with up to 99% ee. To supplement our previous work on the Ir-catalyzed asymmetric hydrogenation of 2-alkyl substituted quinolin-3-amines, a number of 2-aryl substituted substrates were reduced to provide a series of valuable chiral exocyclic amines with high diastereo-and enantioselectivities.O ptically active exocyclic amines exist as key structural elements in many biologically active molecules including natural and unnatural products.1 In addition, they are useful intermediates for organic synthesis and serve as chiral catalysts in various asymmetric transformations. Due to the simplicity and atom efficiency, asymmetric catalytic reduction of exocyclic enamines, imines, and aromatic amines represents a significant approach to these compounds.2 Compared to the various successful examples of the asymmetric hydrogenation of exocyclic enamines and imines, 1,3 little attention has been paid to the asymmetric hydrogenation of aromatic amines due to their high stability of aromaticity and strong coordinating ability. However, catalytic asymmetric hydrogenation of other heteroarenes has been well documented. 4−10Very recently, we reported the first asymmetric hydrogenation of aromatic amines, 2-alkyl substituted quinolin-3-amines, giving the chiral exocyclic amines in excellent yields, with high diastereo-and enantioselectivities.11 However, for the 2-aryl substituted substrate, only a moderate ee value was obtained. In consideration of the successful application of chiral phosphoric acids (CPA) in the asymmetric transfer hydrogenation of CC, CN, and CO double bonds and heteroaromatic compounds with Hantzsch esters (HEH) 12−14 as the hydrogen source, we envision that quinolin-3-amines could also be enantioselectively reduced using this catalyst system (Scheme 1). As a part of our sustained efforts in the asymmetric hydrogenation of aromatic compounds, 4a,b,f and also as a supplement to our previous work, 11 herein, we report an efficient CPA-catalyzed transfer hydrogenation of 2-aryl substituted quinolin-3-amines with excellent diastereo-and enantioselectivities.Initially, 2-phenylquinolin-3-amine was selected as the model substrate. The original experiment was conducted in 1,4-dioxane by using CPA (S)-3a as the catalyst and HEH 2a as the hydrogen source. Unfortunately, no reaction was observed (Scheme 2). Then, the effect of the N-protecting groups of 2-phenylquinolin-3-amine on the reactivity and enantioselectivity was investigated. Several protecting groups were introduced to the amino group, and to our delight, the desired products could be obtained for both the tert-butoxycarbonyl group (Boc) and p-toluenesulfonyl group (Ts) protected substrates while the phthaloyl group (Phth) failed to promote the reaction. The Ts group protected substrate 4-methyl-N-(2-phenylquinolin-3-