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Enantiospecific sp 2 –sp 3 Coupling of ortho ‐ and para ‐Phenols with Secondary and Tertiary Boronic Esters
Author(s) -
Wilson Claire M.,
Ganesh Venkataraman,
Noble Adam,
Aggarwal Varinder K.
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201710777
Subject(s) - chemistry , phenols , phenol , boronic acid , organic chemistry , benzotriazole , stereospecificity , suzuki reaction , natural product , medicinal chemistry , catalysis , palladium
The coupling of ortho ‐ and para ‐phenols with secondary and tertiary boronic esters has been explored. In the case of para ‐substituted phenols, after reaction of a dilithio phenolate species with a boronic ester, treatment with Ph 3 BiF 2 or Martin's sulfurane gave the coupled product with complete enantiospecificity. The methodology was applied to the synthesis of the broad spectrum antibacterial natural product (−)‐4‐(1,5‐dimethylhex‐4‐enyl)‐2‐methyl phenol. For ortho ‐substituted phenols, initial incorporation of a benzotriazole on the phenol oxygen atom was required. Subsequent ortho ‐lithiation and borylation gave the coupled product, again with complete stereospecificity.