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Fe(OTf) 3 ‐Catalyzed α‐Benzylation of Aryl Methyl Ketones with Electrophilic Secondary and Aryl Alcohols
Author(s) -
Pan Xiaojuan,
Li Minghao,
Gu Yanlong
Publication year - 2014
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201300956
Subject(s) - electrophile , aryl , chemistry , alkylation , ketone , friedel–crafts reaction , catalysis , organic chemistry , chlorobenzene , salicylaldehyde , medicinal chemistry , alkyl , polymer chemistry , schiff base
Acid‐catalyzed Friedel–Crafts alkylation of 1,3‐dicarbonyl compounds with electrophilic alcohols, is known to be an effective CC bond forming reaction. However, until now, this reaction has not been amenable for α‐alkylation of aryl methyl ketones because of the notoriously low nucleophilicities of these compounds. Therefore, α‐alkylation of aryl methyl ketone relies on precious metal catalysts and also, the use of primary alcohols is mandatory. In this study, we found that a system composed of a Fe(OTf) 3 catalyst and chlorobenzene solvent is sufficient to promote the title Friedel–Crafts reaction by using benzhydrols as electrophiles. 3,4‐Dihydro‐9‐(2‐hydroxy‐4,4‐dimethyl‐6‐oxo‐1‐cyclohexen‐1‐yl)‐3,3‐dimethyl‐xanthen‐1(2 H)‐one was also applicable as an electrophile in this type of benzylation reaction . On the basis of this result, a three‐component reaction of salicylaldehyde, dimedone, and aryl methyl ketone was also developed, and this provided an efficient way for the synthesis of densely substituted 4H‐chromene derivatives.