6-O-demethylation of the thevinols with lithium aluminium hydride: Selective demethylation of a tertiary alkyl methyl ether in the presence of an aryl methyl ether

S W Breeden, A Coop, S M Husbands, J W Lewis

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In the pursuit of ring-constrained analogues of buprenorphine, we wished to prepare 6-O-demethylated analogues of the thevinols and orvinols. Previously it had been disclosed that lithium aluminum hydride (LAH) in THF containing a chlorinated solvent could achieve this transformation. Here we report the results of our work with LAH in the non-coordinating solvent toluene. In refluxing toluene, the selective 6-O-demethylation of thevinols could be achieved with no 3-O-demethylation being observed. It appears that a C(20)-OH or C(2O)-NH2 group is needed on the substrate for this hydrogenolysis to proceed.

Original languageEnglish
Pages (from-to)1978-1980
Number of pages3
Issue number11
Publication statusPublished - 1999

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