Dearomatization is an important class of transformations in organic chemistry. However, the disruption of aromaticity is generally recognized as thermodynamically unfavorable because of the instability of the corresponding products. Therefore, the precise control of the stereochemistry of the dearomatization processes are extremely challenging. Prof. You coined the term of “catalytic asymmetric dearomatization (CADA) reactions”, and has developed efficient transformations from readily available aromatic starting materials towards diverse densely functionalized spiro and fused polycyclic molecules. The representative works in this area include:
(1) Structural diverse-oriented synthesis and controllable transformations of chiral spiroindolenine derivatives.
(2) Bio-inspired asymmetric dearomative prenylation of indole-derivatives by Pd-catalysis.
(3) Time-dependent enantiodivergent synthesis via sequential kinetic resolution.
(4) Transition-metal-catalyzed Z-retentive asymmetric allylic dearomatization reactions.
Although C–H functionalization is regarded as a prominent strategy in building-up molecular complexity from simple chemical feedstocks, achieving high level of stereoselectivities in this process is by no means an easy task due to the strong bond energy and weak polarity of C–H bonds and the difficulty in distinguishing many C–H bonds in similar chemical environment. Prof. You has developed a series of asymmetric aryl C–H functionalization reactions by Bronsted acid catalysis and transition metal catalysis, which provides expedient synthesis of the target molecules with central, planar, axial or helical chirality. The representative works in this area include:
(1) Chiral phosphoric acid-catalyzed asymmetric Friedel–Crafts alkylation and synergistic effects in sequential reaction with olefin cross-metathesis.
(2) Pd-catalyzed asymmetric functionalization of ferrocene C–H bonds leading to various planar chiral molecules.
(3) Rh-catalyzed asymmetric C–H functionalization towards rapid construction of poly heterocyclic molecules with axial or helical chirality.
The innovation on privileged chiral ligands and catalysts is among the basic solution for achieving high efficiency and selectivity in asymmetric catalysis. Prof. You has developed a series of chiral phosphoramidite ligands (THQphos, BHPphos, Allylphos, etc.), N-heterocyclic carbene precursors derived from camphor or chiral diamines, and chiral cyclopentadienyl ligands (SCp, Cpm, BOCp, etc.) and their Rh-complexes. These chiral ligands and catalysts exhibit superior catalytic performance in many reactions. Some of these ligands are now made commercially available by various chemical vendors.