Facile and Regioselective Dealkylation of Alkyl Aryl Ethers Using Niobium(V) Pentachloride

Abstract

A simple and facile method for the cleavage of carbon-oxygen bonds promoted by niobium pentachloride(V) is described. Excellent yields and regioselectivities were observed with various alkyl aryl ethers to give the phenols. NMR studies revealed the formation of monoaryloxy niobium

An Efficient and Green Synthesis of 1‐Indanone and 1‐Tetralone via Intramolecular Friedel–Crafts Acylation Reaction

“…Furthermore, demethylation, which often occurs for methoxy containing starting materials, did not occur. [49][50][51] The recyclability of Tb(OTf) 3 in [bmim]OTf was confirmed for the intramolecular Friedel-Crafts acylation of three substrates under microwave irradiation. Due to its high solubility in the ionic liquid [bmim]OTf, Tb(OTf) 3 was easily recovered in quantitative yield.…”

Fluorinated Radicamine A and B: Synthesis and Glycosidase Inhibition

“…Compound 16 was first converted into 3‐fluorocatechol11 and then acetylated to give a pair of inseparable isomers 17a and 17b . The mixture of 17a and 17b was methylated to afford 18a and 18b ,12 respectively, as known compounds that could be partially separated by column chromatography. Given the difficulty of separating 18a and 18b in this step, the mixture of the two isomers was directly brominated to 19 and 20 , which were then separated more easily ( 19 / 20 , 2.6:1).…”

“…Data for 18a: 1 H NMR (300 MHz, CDCl 3 ): δ = 6.99–6.94 (m, 2 H, Ph), 6.84–6.80 (m, 1 H, Ph), 3.91 (d, J = 1.8 Hz, 3 H, OMe), 2.30 (s, 3 H, Ac) ppm [ref 12 . 1 H NMR (400 MHz, CDCl 3 ): δ = 6.97–7.02 (m, 2 H), 6.81–6.86 (m, 1 H), 3.93 (d, J = 1.6 Hz, 3 H), 2.33 (s, 3 H) ppm].…”

Nucleophilic Aliphatic Substitution

“…128 The reaction always occurs at the most sterically crowded alkyl group and the alkyl group reactivity decreases in the order benzyl > ethyl > methyl. This suggests that the reaction proceeds via an S N 1 mechanism.…”