Enantiospecific synthesis of the proposed structure of the antitubercular marine diterpenoid pseudopteroxazole: revision of stereochemistry.

T W Johnson, E J Corey

Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.

Journal of the American Chemical Society 2001 May 16

filter terms:

An enantiospecific synthesis of structure 1, previously assigned to the antitubercular marine natural product pseudopteroxazole, has been accomplished as outlined in Scheme 1. Coupling of diene acid 3 and amino phenol 4 produced the amide 5, which was subjected to a novel oxidative intramolecular Diels-Alder reaction to generate the tricyclic lactam 6a stereoselectively. This product was transformed via intermediates 7-11 into the diene 13. Cationic cyclization of 13 afforded two diastereomeric tricyclic amphilectanes which were separated and transformed by parallel four-step sequences into 1 and 2, respectively. Neither 1 nor 2 were identical with pseudopteroxazole, indicating a need for revision of the structure, probably to 16.

Citation

T W Johnson, E J Corey. Enantiospecific synthesis of the proposed structure of the antitubercular marine diterpenoid pseudopteroxazole: revision of stereochemistry. Journal of the American Chemical Society. 2001 May 16;123(19):4475-9