Electrochemical Oxidative [4+2] Annulation of Different Styrenes toward the Synthesis of 1,2-Dihydronaphthalenes

Abstract

A [4+2] annulation of two different styrenes to construct polysubstituted 1,2-dihydronaphthalenes was achieved. This transformation proceeded smoothly under electrochemical oxidative conditions without metal catalysts and external oxidants. A series of polysubstituted 1,2-dihydronaphthalenes were obtained with high regioselectivity and diastereoselectivity. Moreover, polysubstituded 1,2-dihydronaphthalenes were further transformed to polysubstituted 1,2,3,4-tetrahydronaphthalenes and polysubstituted naphthalenes, which showed great potentials in synthetic application.

Chemical Synthesis of Substituted Naphthalene Derivatives: A Review

“…46 In 2020, Yin and co-workers reported a one-pot synthesis of diamino-substituted naphthalenes 131 in a domino process that includes the formation of 2 C-N bonds, 3 C-C bonds, and one aromatic ring (Scheme 17). 47 The reaction of aryl halides 128, 1,4-bis(trimethylsilyl)butadiyne (129), and amine substrates 130 in DMF at 80 °C under the coop- M. Maheshwari, N. Hussain…”

“…Also in 2022 Lu, Lei, and co-workers reported an electrochemical reaction for the oxidative annulation of styrenes 826 and 827 in an undivided cell using tris(4-bromophenyl)amine as a mediator, n -Bu 4 NClO 4 as an electrolyte, and a mixed solvent of acetonitrile and hexa­fluoroisopropanol at r.t. under nitrogen for 4 h to give 1,2-dihydronaphthalenes 828 (Scheme 116 ). 129 Styrene 826 containing an α-methyl substituent (R 2 ) gave dihydronaphthalenes such as 829 to 834 in 47–78% yield. Substitution in the benzene ring of the styrene (R 1 ) such as tert -butyl and bromo gave 831 and 833 , respectively, in 56% and 47% yield.…”

N-Hydroxyphthalimide-Mediated Electrochemical Denitrogenation of Aroylhydrazides to Generate Acyl Radicals and Their Applications in the Syntheses of Fluorenones

“…Organic electrosynthesis utilizes electrons as the oxidants to access diverse reactive intermediates under mild conditions, and it has emerged as an innovative tool for organic synthesis . Previous reports on the electrochemical generation of sulfonyl radicals from arylsulfonylhydrazines encourage us to propose the possibility of electrochemical denitrogenation of aroylhydrazides .…”