With a dual organocatalytic system involving a chiral phosphoric acid and a dicyanopyrazine-derived chromophore (DPZ) photosensitizer and under the irradiation with visible light, an enantioselective Minisci-type addition of α-amino acid-derived redox-active esters (RAEs) to isoquinolines has been developed. A variety of prochiral α-aminoalkyl radicals generated from RAEs were successfully introduced on isoquinolines, providing a range of valuable α-isoquinoline-substituted chiral secondary amines in high yields with good to excellent enantioselectivities.

Summary The site-specific incorporation of deuterium (D) into small molecules is frequently used to access isotopically labeled compounds with broad utility in many research areas, such as drug development, mechanistic studies, and NMR analyses. Nevertheless, the deuteration of a stereocenter in an enantioselective manner, which could slow the metabolism and improve the bioavailability of bioactive molecules, remains challenging owing to the lack of established catalytic methods. Here, we report an asymmetric α-deuteration strategy for azaarenes with inexpensive D 2 O as the deuterium source. A cooperative visible light-driven photoredox and chiral Brønsted acid–catalyzed system using a Hantzsch ester as the terminal reductant has been developed, which enables racemic α-chloro-azaarenes and prochiral azaarene-substituted ketones to experience a single-electron reduction–enantioselective deuteration process. The transition metal-free method provides important chiral α-deuterated azaarenes in satisfactory yields with good to excellent enantioselectivities (up to 99% ee) and substantial deuterium incorporation.

A visible‐light‐driven sequential photoredox catalysis to allow N‐aryl α‐amino acids to experience efficient cascade aerobic decarboxylative Povarov and oxidative dehydrogenation (ODH) reactions is described. With a dicyanopyrazine‐derived chromophore (DPZ) as a photoredox catalyst in both transformations, two series of valuable azaarenes, i. e., 4‐amino tetrahydroquinolines (THQs) and quinolines, were obtained in satisfactory yields featuring diverse 2‐ and 2,3‐substituent patterns. To enable the ODH reaction of 4‐amino THQs, a cooperative catalysis with N‐hydroxyphthalimide was developed. Additionally, an unprecedented synthesis of chiral N‐amino‐2‐methyl THQs with high enantioselectivities was realized.magnified image

An efficient highly regio- and stereoselective iron-catalyzed conjugate addition of 2,3-allenoates with primary or secondary alkyl, phenyl, or vinyl Grignard reagents to synthesize multi-substituted beta,gamma-unsaturated enoates has been reported. The in situ formed magnesium dienolate may readily react with different electrophilic reagents to construct an allylic quaternary carbon at the alpha-position of the ester group.

An efficient method for synthesis of polysubstituted cyclobutenones, which are not readily available from traditional methods due to the intrinsic ring strain, is described. The reaction of 2,3-allenoates and organozinc reagents proceeds via a tandem Michael addition/cyclic 1,2-addition/elimination mechanism with the functional groups from the organozinc reagents being introduced to the 3-position of the cyclobutenone products regiospecifically in moderate to excellent yields. Application to the synthesis of stereodefined β,γ-unsaturated enones is demonstrated.