Organocatalytic Asymmetric Dearomatization Reaction for the Construction of Axially Chiral Urazole Embedded Naphthalenones

Abstract

Herein we disclose a catalytic asymmetric dearomatization reaction of β‐naphthols with 4‐aryl‐1,2,4‐triazole‐3,5‐diones. A chiral phosphoric acid with spiro motif was found to be effective for this reaction. The chiral urazole embedded naphthalenones having both axial and central chirality were obtained in good to high yields (70–85%) with high diastereo‐ and enantioselectivities (>20:1, 8–96% ees), having C−N rotational energy barrier 31.54 K.Cal.mol−1 and t1/225 °C=589.8 years. The scope of the reaction was broad and few applications including a bromo‐amination reaction have been demonstrated.

Organocatalytic enantioselective synthesis of Csp2–N atropisomers via formal Csp2–O bond amination

“…1B ), the catalytic asymmetric synthesis of these atropisomeric scaffolds is seldom reported due to their inherently less stable configuration and lower rotational barrier. 5 Traditional strategies for the construction of such enantioenriched frameworks rely on the functional group conversion of the existing C sp 2 –N axis, 6 such as N -functionalizations, 7 desymmetrizations, 8 asymmetric cyclizations. 9 Although central-to-axial chirality conversion can induce chiral C–N axes, it is not a one-step synthesis.…”

Chiral cobalt(ii) complex-promoted asymmetric para-Claisen rearrangement of allyl α-naphthol ethers

“…Asymmetric dearomatization of naphthol derivatives is an efficient method to build chiral naphthalenone skeletons. 5 However, compared to well-established oxidative 6 or transition metal mediated 7 dearomatizations, rearrangement-based 8 dearomatizations are relatively less explored. The aromatic [ n , m ]-sigmatropic rearrangement of allyl or propargyl naphthyl ethers can rapidly construct allyl or propargyl functionalized naphthalenones.…”