Synthesis of a 4,6-Disubstituted Dibenzofuran β-Sheet Initiator by Reductive Radical Arylation of Benzene

Abstract

[reaction: see text] Tributyltin hydride mediated addition of 3-iodosalicylaldehyde to benzene in the presence of catalytic benzeneselenol affords (1,4-cyclohexadien-3-yl)salicylaldehyde. Homologation of the aldehyde group is followed by cycloetherification with dimethyl dioxirane to give a 4,6-disubstituted tetrahydrodibenzofuran. Adjustment of oxidation states and introduction of a second chain by Wittig olefination affords the beta-sheet initiator, ethyl 4-(2-tert-butoxycarbonylaminoethyl)-6-dibenzofuranpropanoate.

Chiral Seleno-Amines from Indium Selenolates. A Straightforward Synthesis of Selenocysteine Derivatives

“…Reduction of Se−Se bonds, especially cleavage of diphenyl or diaryl diselenides, has recently received much effort for the preparation of unsymmetrical diorganyl selenides. Chemical cleavage of Se−Se bonds in diaryl diselenides was realized with reducing agents such as NaBH 4 , Na/NH 3 , Bu 3 SnH, and LiAlH 4 selenoesters, and β-hydroxy selenides with special attention given to unsymmetrical diorganyl selenides …”

Expedient Two-Step Synthesis of Phenolic Cyclitols from Benzene

“…The synthetic utility of this reaction has been exploited in the case of aryl iodides bearing a nucleophile at the o -position when subsequent electrophilic activation of the cyclohexadiene moiety gives direct access to functionalized tetrahydrocarbazoles and tetrahydrodibenzofurans, as displayed in syntheses of carbazomycin and of a 4,6-substituted dibenzofuran β -sheet initiator …”

Reaction of Acyl Chlorides withIn SituFormed Zinc Selenolates: Synthesis of SelenoestersversusRing-Opening Reaction of Tetrahydrofuran

“…The incorporation of selenium into organic compounds can be conveniently achieved using nucleophilic reagents such as selenols or selenolates, which can be generated in situ via a reductive cleavage of the Se-Se bond starting from a diselenide. Commonly used protocols for generating selenolates involve the use of several reducing agents, such as NaBH 4 , LiAlH 4 , and other expensive and often not easily handled metal sources [5][6][7][8].…”