0 citations0 references

Mechanistic Investigation on Dearomative Spirocyclization of Arenes with α-Diazoamide under Boron Catalysis

ACS Catalysis2022Vol. 13(1), pp. 147–157

Citations Over TimeTop 23% of 2022 papers

Tsubasa Ito, Shingo Harada, Haruka Homma, Ayaka Okabe, Tetsuhiro Nemoto

Abstract

Controlling extremely active species remains a formidable challenge in synthetic organic chemistry. Although carbene species with high and divergent reactivities can access reaction manifolds, precious transition metals are commonly required as the catalyst for controlling the selectivity. Herein, we report a mechanistic study on borane-catalyzed chemoselective dearomatizations using carbene-equivalent species. Reaction coordinate diagram and multiple theoretical studies based on non-covalent interaction-plotting, natural energy decomposition analysis, and the distortion–interaction model revealed that the activation model with a B–C bond is more promising than the previously proposed Lewis acid model possessing B–N and B–O bond linkages. In addition, a mechanistic analysis indicated that an intermediate state was significantly stabilized by B–C bonding and neighboring-group participation of the amide functionality. Overall, harnessing non-covalent interactions along with the stabilizing effects enabled control of the reactive species, leading to dearomatization reactions of diverse aromatic compounds. Combinations of the borane catalyst and terminal diazoamides as the carbene precursor realized dearomative spirocyclizations, some of which cannot be achieved under metal catalysis. Products with a spirocyclic motif have a privileged scaffold for the synthesis of bioactive molecules and pharmaceuticals possessing a nitrogen-containing ring system.

Citations Over TimeTop 23% of 2022 papers

Abstract

Related Papers