Synthesis of Pentacyclic Steroids via Tandem Stille Coupling and Diels−Alder Reactions

Autor:	Judit Horvath, György Jeges, László Kollár, Zoltan Tuba, Rita Skoda-Földes
Rok vydání:	1997
Předmět:	Dimethyl acetylenedicarboxylate chemistry.chemical_compound chemistry Tandem Organic Chemistry Diels alder Maleic anhydride Organic chemistry Stereoselectivity Methyl acrylate Cycloaddition Stille reaction
Zdroj:	The Journal of Organic Chemistry. 62:1326-1332
ISSN:	1520-6904 0022-3263
DOI:	10.1021/jo9615256
Popis:	Tandem Stille coupling and Diels−Alder reaction of steroidal iodoalkenyl substrates [17-iodoandrosta-16-ene (2), 17-iodo-3-keto-4-methyl-4-azaandrosta-16-ene (10), and 17-iodo-3-keto-4-azaandrosta-16-ene (11)] were examined in the presence of vinyltributyltin, a dienophile (diethyl maleate, methyl acrylate, dimethyl acetylenedicarboxylate, diethyl fumarate, (−)-di[(1R)-menthyl] fumarate, maleic anhydride), and a palladium catalyst. The yields of novel pentacyclic steroids and the stereochemical outcome of the cycloaddition reaction were investigated under different reaction conditions. In some cases mixtures of isomers were formed, but with dimethyl acetylenedicarboxylate, diethyl fumarate, (−)-di[(1R)-menthyl] fumarate, and maleic anhydride the products could be produced in good yields with high stereoselectivity. The unequivocal assignment of stereoisomers was carried out by various NMR techniques including 1H−1H COSY and NOE experiments.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::397f76da0a5375ee8dcc06ff19ce5473 https://doi.org/10.1021/jo9615256 Zobrazit plný text záznamu