Intramolecular Conjugate Addition of α,β-Unsaturated Lactones Having an Alkanenitrile Side Chain: Stereocontrolled Construction of Carbocycles with Quaternary Carbon Atoms

Autor:	Keiji Tanino, Fumihiko Yoshimura, Makoto Torizuka, Genki Mori
Rok vydání:	2012
Předmět:	cyclization Stereochemistry Chemistry carbocycles Organic Chemistry Stereocenter Michael addition Intramolecular force Side chain Michael reaction nitriles stereoselective synthesis Conjugate Quaternary carbon
Zdroj:	Synlett. 2012:251-254
ISSN:	1437-2096 0936-5214
DOI:	10.1055/s-0031-1290074
Popis:	An efficient method for constructing carbocycles with all-carbon quaternary stereocenters has been developed on the basis of a stereoselective cyclization reaction of α,β-unsaturated lactones having an alkanenitrile side chain. Treatment of the substrate with lithium hexamethyldisilazide (LiHMDS) in the presence of triisopropylsilyl chloride (TIPSCl) led to the generation of the corresponding α-cyano carbanion species which readily underwent an intramolecular conjugate addition reaction. It was found that the combined use of trimethylsilyl trifluoromethanesulfonate (TMSOTf) and triethylamine is also effective for the cyclization reaction without using a strong base. Interestingly, different stereochemical outcomes were observed in the two cyclization methods.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7d3a9cf598015e1f4bb77c8aeaa4244e https://doi.org/10.1055/s-0031-1290074 Zobrazit plný text záznamu