Intriguing formal [2+3] cycloaddition promoted by a hypervalent iodine reagent

Rhodium‐Catalyzed [3+2]‐Annulation of ortho‐Diazoquinones with Enol Ethers: Diversity‐Oriented Total Synthesis of Aflatoxin B2

“…6-Bromo-3,4,4 a,9 a-tetrahydro-2H-pyrano[2, 3-b]benzofuran (4 ab). [8] Orange oil (42 mg, 82 %). TLC: R f 0.3 (9 : 1 hexanes/EtOAc).…”

“…For example, the Canesi group in 2008 demonstrated [3 + 2]-cycloaddition of phenols with furan, allylsilanes, enol ethers, and electron-rich olefins using hypervalent iodine reagent (Scheme 1a). [8] However, this method exerts an insufficient degree of regiocontrol. Later, the Mazet group developed a method for synthesizing tetrahydrofurobenzofurans via a Pd-catalyzed enantioselective carboetherification of dihydrofurans (Scheme 1b).…”

Total Synthesis of (±)-Decursivine via BINOL-Phosphoric Acid Catalyzed Tandem Oxidative Cyclization

“…In the literature, hypervalent iodine have been used for the oxidative [3+2] cycloaddition of various phenols and styrenes to give 2,3dihydrobenzofuran derivatives. [20][21][22][23][24] So, we treated compound 8 with hypervalent iodine reagent bis(tri uoroacetoxy)iodo)benzene (PIFA), and the product 1 was obtained in 48% yield (entry 7). Moderate yield of the product could be due to the decomposition of some of the in situ formed quinone cycloaddition.…”

Asymmetric Iodoetherification of Isosorbide-Derived Glycals: A Regio- and Stereoselective Access to a Variety of O-Substituted Isosorbide Derivatives

“…Moreover, they could be stored in a freezer (−18 °C) under argon for weeks without noticeable decomposition. However acidic conditions promote a rearrangement that leads to the corresponding mono protected 2-furanylethanediol [30,31].…”