Allylamines are important building blocks in the synthesis of bioactive compounds. The direct coupling of allylic CÀ H bonds and commonly available amines is a major synthetic challenge. An allylic CÀ H amination of 1,4-dienes has been accomplished by palladium catalysis. With aromatic amines, branchselective allylic aminations are favored to generate thermodynamically unstable Z-allylamines. In addition, more basic aliphatic cyclic amines can also engage in the reaction, but linear dienyl allylic amines are the major products.

A light-mediated asymmetric dicarbofunctionalization of enamides with carboxylic-acid-derived redox-active esters (RAEs) and indoles has been established by using chiral lithium phosphate catalysis in the presence or absence of photoredox catalyst. This reaction features mild reaction conditions and broad substrate scopes, delivering a wide range of highly functionalized chiral amine derivatives. Mechanistic studies suggest that chiral lithium phosphate can serve as a pocket to accelerate the aggregation of enamide and RAE through hydrogen-bonding and coordination interaction, enabling the formation of a charge-transfer complex (CTC). Either enamide or CTC can be excited by direct irradiation or Ru­(II)-mediated photosensitization to furnish chiral iminium intermediates for the asymmetric Friedel–Crafts reaction of indole.

In the presence of visible-light photoredox and chiral phosphate catalysts, a novel asymmetric Friedel−Crafts reaction of indoles and readily accessible α-amino acid derived redox-active esters is established to afford enantioenriched 1indolyl-1-alkylamine derivatives in moderate to high yields and with high levels of enantioselectivities. This method not only shows a mild and efficient alternative for the in situ generation of N-acyl imines but also indicates the feasibility of a multicatalyst system for asymmetric photoredox catalysis.N-Acyl imines are valuable building blocks to access versatile nitrogen-containing compounds. 1 Asymmetric transformation of these compounds represents one of the fundamental issues in chiral Brønsted acid or transition-metal catalysis and hold great synthetic value. 2 In particular, N-acyl aliphatic imines can easily isomerize to the corresponding N-acyl enamines; hence, considerable efforts have been devoted to the development of stable N-acyl imine precursors. 1c Among them, conventionally employed precursors are α-amidosulfones 3 (Scheme 1a).

A palladium-catalyzed asymmetric intramolecular allylic C-H amination controlled by a chiral phosphoramidite ligand was established for the preparation of various substituted chiral hydropyrimidinones, the precursors of hydropyrimidines, in high yields with high enantioselectivities. In particular, dienyl sodium N-sulfonyl amides bearing an arylethene-1-sulfonyl group underwent a sequential allylic C-H amination and intramolecular Diels-Alder (IMDA) reaction to produce chiral fused tricyclic tetrahydropyrimidinone frameworks in high yields and with high levels of stereoselectivity. Significantly, this method was used as the key step in an asymmetric synthesis of letermovir.