Enantiospecific sp² -sp³ Coupling of ortho- and para-Phenols with Secondary and Tertiary Boronic Esters.

ABSTRACT: 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 Ph₃ BiF₂ 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.

SUBMITTER: Wilson CM 

PROVIDER: S-EPMC5767764 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature