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Review
. 2024 Dec 13:12:1470861.
doi: 10.3389/fchem.2024.1470861. eCollection 2024.

Novel transition metal-free synthetic protocols toward the construction of 2,3-dihydrobenzofurans: a recent update

Aqsa Mushtaq  1 , Muhammad Irfan  2 , Atta Ul Haq  1 , Asim Mansha  1 , Samreen Gul Khan  1 , Ameer Fawad Zahoor  1 , Bushra Parveen  1 , Ali Irfan  1 , Katarzyna Kotwica-Mojzych  3 , Mariola Glowacka  4 , Mariusz Mojzych  4
Affiliations
Review

Novel transition metal-free synthetic protocols toward the construction of 2,3-dihydrobenzofurans: a recent update

Aqsa Mushtaq et al. Front Chem. .

Abstract

2,3-Dihydrobenzofurans are noteworthy scaffolds in organic and medicinal chemistry, constituting the structural framework of many of the varied medicinally active organic compounds. Moreover, a diverse variety of biologically potent natural products also contain this heterocyclic nucleus. Reflecting on the wide biological substantiality of dihydrobenzofurans, several innovative and facile synthetic developments are evolving to achieve these heterocycles. This review summarizes the transition-metal-free, efficient, and novel synthetic pathways toward constructing the dihydrobenzofuran nucleus established after 2020.

Keywords: catalyst free; dihydrobenzofurans; organocatalyzed; photocatalytic; transition metal-free.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

FIGURE 1
FIGURE 1
General structure of dihydrobenzofuran 1.
FIGURE 2
FIGURE 2
Structures of the dihydrobenzofuran ring constituting biologically active natural products.
SCHEME 1
SCHEME 1
Synthesis of dihydrobenzofurans 8 and 11 using a Bronsted acid as the catalyst.
SCHEME 2
SCHEME 2
Synthesis of dihydrobenzofurans 14 and 17 using a Bronsted acid as the catalyst.
SCHEME 3
SCHEME 3
Synthesis of dihydrobenzofurans 19 and 22 using a Bronsted acid as the catalyst.
SCHEME 4
SCHEME 4
Synthesis of dihydrobenzofurans 25 and 27 using a Bronsted acid as the catalyst.
SCHEME 5
SCHEME 5
Synthesis of dihydrobenzofuran 30 using a Bronsted–Lewis acid as the catalyst.
SCHEME 6
SCHEME 6
Synthesis of dihydrobenzofuran 34 by a photocatalytic reaction.
SCHEME 7
SCHEME 7
Synthesis of dihydrobenzofuran 36 by a photocatalytic reaction.
SCHEME 8
SCHEME 8
Synthesis of dihydrobenzofuran 38 by a photocatalytic reaction.
SCHEME 9
SCHEME 9
Synthesis of dihydrobenzofuran 41 by a photocatalytic reaction.
SCHEME 10
SCHEME 10
Synthesis of dihydrobenzofuran 43 by a photocatalytic reaction.
SCHEME 11
SCHEME 11
Synthesis of dihydrobenzofurans 47 and 48 by a photocatalytic reaction.
FIGURE 3
FIGURE 3
Proposed mechanism for the synthesis of dihydrobenzofuran 47 by a photocatalytic reaction.
FIGURE 4
FIGURE 4
Structure of natural products constituting dihydrobenzofuran skeleton 5 and 49.
SCHEME 12
SCHEME 12
Synthesis of dihydrobenzofurans 52 and 52′ by a photocatalytic reaction.
SCHEME 13
SCHEME 13
Synthesis of dihydrobenzofuran 55 by a photocatalytic reaction.
SCHEME 14
SCHEME 14
Synthesis of the dihydrobenzofuran derivative 61 by a base-induced reaction.
SCHEME 15
SCHEME 15
Synthesis of the dihydrobenzofuran derivative 64 by a base-induced reaction.
SCHEME 16
SCHEME 16
Synthesis of the dihydrobenzofuran derivative 66 and 66′ by a base-induced reaction.
SCHEME 17
SCHEME 17
Synthesis of the dihydrobenzofuran derivative 69 by a base-induced reaction.
SCHEME 18
SCHEME 18
Synthesis of the dihydrobenzofuran derivative 73 by a base-induced reaction.
SCHEME 19
SCHEME 19
Synthesis of the dihydrobenzofuran derivative 76 by a base-induced reaction.
SCHEME 20
SCHEME 20
Synthesis of dihydrobenzofuran derivatives 79, 80, and 82 by a base-induced reaction.
FIGURE 5
FIGURE 5
Proposed mechanism for the synthesis of the dihydrobenzofuran derivative 79 using a base-induced reaction.
See this image and copyright information in PMC

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