Organocatalytic Enantioselective Synthesis of Seven‐Membered Ring with Inherent Chirality

Abstract

Inherent chirality is used to describe chiral cyclic molecules devoid of central, axial, planar, or helical chirality and has tremendous applications in chiral recognition and enantioselective synthesis. Catalytic and divergent syntheses of inherently chiral molecules have attracted increasing interest from chemists. Herein, we report the enantioselective synthesis of inherently chiral tribenzocycloheptene derivatives via chiral phosphoric acid (CPA)‐catalyzed condensation of cyclic ketones and hydroxylamines. This chemistry paves the way to accessing the less stable derivatives of 7‐membered rings with inherent chirality. A series of chiral tribenzocycloheptene oxime ethers was synthesized in good yields (up to 97%) with excellent enantioselectivities (up to 99% ee).

Catalytic asymmetric synthesis of planar-chiral dianthranilides via (Dynamic) kinetic resolution

“…Herein, we set our goal to develop direct catalytic asymmetric methods to access conformationally stable planar-chiral dianthranilides with the ability to achieve chiral induction via asymmetric catalysis. To obtain rigid conformers, inhibiting boat-to-boat ring inversion is key 55 , 56 . We assume that N-alkylated dianthranilides 3 - 5 are more conformationally stable and that their catalytic asymmetric synthesis could be enabled by dynamic kinetic resolution (DKR) or kinetic resolution (KR) (Fig.…”

Catalytic Atroposelective Synthesis of Axially Chiral Heterobiaryl Oxime Ethers via the One-Step Dynamic Kinetic Condensation Reaction

“…To our knowledge, the one-step condensation reaction between the CO bond and −NH 2 group represents an irreplaceable and highly efficient transformation step to synthesize imines, which play important roles not only in biological systems but also in the synthesis of fine chemicals . However, since the direct condensation process does not generate new stereocenters at the reaction site, the current asymmetric condensation reactions of carbonyl and amine are mainly limited to the synthesis of novel imines with central chirality or specially axially chiral cyclohexene motifs (Scheme c). Although the atroposelective synthesis of heterobiaryls by the cyclization reaction of configurationally labile azabiaryl aldehyde with anthranilamide has been reported recently, the atroposelective cyclocondensation reaction via imine formation followed by intramolecular nucleophilic addition/oxidative dehydrogenation process was also developed by Tan’s group .…”