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Ti(lll)-Catalyzed Cyclizations of Ketoepoxypolyprenes: Control over the Number of Rings and Unexpected Stereoselectivities.

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Bibliographic Details
Title: Ti(lll)-Catalyzed Cyclizations of Ketoepoxypolyprenes: Control over the Number of Rings and Unexpected Stereoselectivities.
Authors: Morcillo, Sara P.1, Miguel, Delia1, Resa, Sandra1, Martín-Lasanta, Ana1, Millán, Alba1, Choquesillo-Lazarte, Duane2, García-Ruiz, Juan M.2, Mota, Antonio J.3 mota.avila@gmail.com, Justicia, José1 jjusti@ugr.es, Cuerva, Juan M.1 jmcuerva@ugr.es
Source: Journal of the American Chemical Society. 5/14/2014, Vol. 136 Issue 19, p6943-6951. 9p.
Subjects: Titanium catalyst activity, Ring formation (Chemistry), Stereoselective reactions, Catalysis, Stereochemistry
Abstract: We describe a new strategy to control the number of cyclization steps in bioinspired radical (poly)- cyclizations involving epoxypolyenes containing keto units positioned along the polyene chain. This approach provides an unprecedentedly straightforward access to natural terpenoids with pendant unsaturated side chains. Additionally, in the case of bi- and tricyclizations, decalins with cis stereochemistry have been obtained as a consequence of the presence of the ketone. The preferential formation of cis-fused adducts was rationalized using DFT calculations. This result is completely unprecedented in biomimetic cyclizations and permits the access to natural terpenoids with this stereochemistry, as well as to non-natural analogues. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
Description
Abstract:We describe a new strategy to control the number of cyclization steps in bioinspired radical (poly)- cyclizations involving epoxypolyenes containing keto units positioned along the polyene chain. This approach provides an unprecedentedly straightforward access to natural terpenoids with pendant unsaturated side chains. Additionally, in the case of bi- and tricyclizations, decalins with cis stereochemistry have been obtained as a consequence of the presence of the ketone. The preferential formation of cis-fused adducts was rationalized using DFT calculations. This result is completely unprecedented in biomimetic cyclizations and permits the access to natural terpenoids with this stereochemistry, as well as to non-natural analogues. [ABSTRACT FROM AUTHOR]
ISSN:00027863
DOI:10.1021/ja411942h