Tandem S_N2 Nucleophilic Substitution/Phospho-Dieckmann Reaction: One-Step Synthesis of 2-Phosphonyl-3-hydroxybenzo[b]thiophenes

Abstract

A novel and efficient tandem S N 2 nucleophilic substitution/Dieckmann condensation reaction of α-iodomethyl phosphine oxide with methyl thiosalicylate derivatives has been developed by using NaOH as a base, which enables the expeditious synthesis of 2-phosphonyl-3-hydroxybenzo[b]thiophene derivatives in moderate to high yields under simple conditions. This research provides not only a convenient method for the functionalization of benzo[b]thiophenes at the 2-position and 3-position but also new organophosphorus molecules. Furthermore, several new phosphonyl-substituted benzo[b]thiophenes were obtained from the resultant 2-phosphonyl-3-hydroxybenzo[b]thiophenes.

Selective C2 and C3 phosphorylmethylation of indoles with a phosphorylmethyl dibenzothiophenium reagent

“…Generally, ICH 2 PO(OEt) 2 and TsOCH 2 PO(OEt) 2 are the most convenient and commercially available sources of -CH 2 PO(OEt) 2 . 7 c ,12 In 2013, A. Baba and co-workers reported the radical coupling of ICH 2 PO(OEt) 2 with organostannanes under the catalysis of indium halide (III) and UV irradiation. 12 a Subsequently, Yang's group studied the Catellani reaction of indoles catalyzed by palladium with ICH 2 PO(OEt) 2 , efficiently introducing –CH 2 PO(OEt) 2 into the C2 position.…”