Organocatalytic Asymmetric Synthesis of Tetrahydrofuran and 1,2‐Dihydrobenzofuran Scaffolds

Abstract

Asymmetric synthesis of substituted tetrahydrofurans and dibenzofurans is emerging as a challenging field. Use of organocatalysis has been explored extensively to achieve the asymmetry involves mild conditions and control over enantio‐ and diastereoselectivity for the synthesis of substituted THF and DHB. A review of various conditions and catalysts developed so far towards the synthesis of substituted tetrahydrofuran and dibenzofuran are presented here.

Asymmetric β-arylation of cyclopropanols enabled by photoredox and nickel dual catalysis

“…Alternatively, treatment of 8 with hydrogen chloride solution (1.0 M in 1,4-dioxane) led to tetrahydrofuran derivative 10 ( Scheme 2D ), which is a privileged structural unit in natural products and bioactive compounds. 23 …”

Oxyselenocyclization of 2‐Allylphenols for the Synthesis of 2,3‐Dihydrobenzofuran Selenides

“…As a consequence of the diverse panel of biological activity displayed by these compounds, several synthetic procedures have been developed to access the 2,3‐DHB core. Some of the most efficient methods reported in the literature involve radicalar [18–24] or anionic cyclizations, [25–28] biomimetic couplings, [29–34] cycloaddition processes, [35–40] reactions mediated by Lewis acids [41–45] or transition‐metals [46–50] among other strategies [51–56] …”

“…Some of the most efficient methods reported in the literature involve radicalar [18][19][20][21][22][23][24] or anionic cyclizations, [25][26][27][28] biomimetic couplings, [29][30][31][32][33][34] cycloaddition processes, [35][36][37][38][39][40] reactions mediated by Lewis acids [41][42][43][44][45] or transition-metals [46][47][48][49][50] among other strategies. [51][52][53][54][55][56] In parallel, organoselenium compounds continue to attracted considerable attention of the scientific community, initially because of their biological activities [57,58] and in the past decades due to their wide range of applications in materials science and in chemical transformations (e. g. as reaction intermediates or catalysts). [59][60][61][62] Among the plethora of methods to prepare organoselenium compounds, one of the most useful approaches is the addition of electr...…”

Squaramide-Catalyzed Asymmetric Intramolecular Oxa-Michael Reaction of α,β-Unsaturated Carbonyls Containing Benzyl Alcohol: Construction of Chiral 1-Substituted Phthalans

“…Oxygen-containing heterocycles are privileged motifs and have attracted immense attention in recent times due to their widespread presence in natural products and biologically active compounds, as well as their increasing importance in the fields of pharmaceuticals and fine chemicals. Therefore, the development of new synthetic methodologies for these oxacyclic frameworks, especially in their chiral forms, is of great interest in organic synthesis . In particular, chiral 1,3-dihydroisobenzofuran, commonly referred to as phthalan, is abundant in bioactive natural products, which display pharmacological properties such as antibacterial, anti-inflammatory, antidepressive, antioxidant, and anti-influenza (Figure ).…”