Intermolecular dearomative [4 + 2] cycloaddition of naphthalenes via visible-light energy-transfer-catalysis

Abstract

Dearomative cycloaddition reaction serves as a blueprint for creating sp3-rich three-dimensional molecular topology from flat-aromatic compounds. However, severe reactivity and selectivity issues make this process arduous. Herein, we describe visible-light...

Photocatalyzed [2σ + 2σ] and [2σ + 2π] Cycloadditions for the Synthesis of Bicyclo[3.1.1]heptanes and 5- or 6-Membered Carbocycles

“…With naphthalene as the aromatic moiety, product 2n was obtained in 68% yield. We did not observe the formation of dearomatized products in contrast to previous reports on the dearomative cyclization of naphthyl alkyl ketones and olefins. , We speculate that the dimethyl substituent on the cyclopropane would stabilize the biradical intermediate, favoring the ring-opening pathway over the cyclization on the naphthyl ring. We then investigated the scope of alkyne partners.…”

Energy transfer photocatalysis: exciting modes of reactivity

“…Several subsequent works were reported exploiting a similar principle of exciting the core organic molecule followed by olefin trapping, and vice versa . 60–65 Parallelly, You and coworkers also reported a double dearomative intramolecular [4+2]-cycloaddition engaging an indole and a pendant naphthalene moiety. 66…”

Photosensitized [4+2]‐ and [2+2]‐Cycloaddition Reactions of N‐Sulfonylimines

“…[5] Further studies led to the development of an intermolecular dearomative cycloaddition with electron deficient naphthalenes. [6] While this reaction did display good regioselectivity, the diastereoselectivity was poor. In this study, we present a solution to this challenge through the use of a sulfonyl imine activating group.…”

“…Based on prior reports, the reaction of electron deficient naphthalenes with β-methyl styrene generates the corresponding [4+2] cycloaddition products with poor diastereoselectivity. [6] One possible explanation for the poor selectivity is due to a similar interaction between the Me group and either the planar aryl group or carbonyl groups (Scheme 2A). To address this issue, we hypothesized that introduction of a larger 3D activating group would significantly differentiate the two diasteromeric transition states such that high diastereoselectivity may be observed (Scheme 2B).…”