Synthesis of an (±)-Estrone Precursor: The Scope of Zr- and Co-Mediated Cycloannulations

Autor:	Robert Betík, Pavel Herrmann, Martin Kotora
Rok vydání:	2010
Předmět:	chemistry.chemical_classification Addition reaction Ketone Pauson–Khand reaction Organic Chemistry Chemical synthesis chemistry.chemical_compound chemistry Organic chemistry Physical and Theoretical Chemistry Chemoselectivity Carbonylation Ene reaction Derivative (chemistry)
Zdroj:	European Journal of Organic Chemistry. 2010:646-655
ISSN:	1099-0690 1434-193X
DOI:	10.1002/ejoc.200900937
Popis:	The synthesis of an estrone intermediate based on a new approach was studied. The construction of the basic framework was carried out in three steps from a simple styrene derivative. The crucial reaction sequence for the steroid skeleton construction relied on a Zr-mediated cyclization (Zr-ene reaction)/propargylation followed by a Co-mediated diastereoselective Pauson―Khand reaction that afforded various D-ring-substituted tetracyclic ketones 11 with natural trans-anti stereochemistry. The conjugated addition reaction of Me 2 Cu-Li to tetracyclic ketone 11a aiming at the installation of the angular methyl group in the 13-position gave rise exclusively to product 12 with unnatural trans-anti-cis stereochemistry The successful synthesis of known estrone intermediate 4 with natural trans-anti-trans stereochemistry was accomplished by chemoselective reduction of the carbonyl group of ketone 11b. Attempts to use other metallo-ene reactions to affect the synthesis of steroid B-ring are also described.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::0f44a37a9fe2d85cb4100fcc3bd509e2 https://doi.org/10.1002/ejoc.200900937 Zobrazit plný text záznamu Plný text