Work

Enantioselective Total Syntheses of (−)-Taiwaniaquinone H and (−)-Taiwaniaquinol B by Iridium-Catalyzed Borylation and Palladium-Catalyzed Asymmetric α-Arylation

Year: 2011

Type: article

Abstract: We report a concise, enantioselective total synthesis of (-)-taiwaniaquinone H and the first enantioselective total synthesis of (-)-taiwaniaquinol B by a route that includes asymmetric palladium-catalyzed α-arylation of a ketone with an aryl bromide that was generated by sterically controlled halogenation via iridium-catalyzed C-H borylation. This asymmetric α-arylation creates the benzylic quaternary stereogenic center present in the taiwaniaquinoids. The synthesis was completed efficiently by developing a Lewis acid-promoted cascade to construct the [6,5,6] tricyclic core of an intermediate common to the synthesis of a number of taiwaniaquinoids. Through the preparation of these compounds, we demonstrate the utility of constructing benzylic quaternary stereogenic centers, even those lacking a carbonyl group in the α-position, by asymmetric α-arylation.

Source: Journal of the American Chemical Society

DOI: 10.1021/ja110215b

Authors: Xuebin Liao, Levi M. Stanley, John F. Hartwig

Institution: University of Illinois Urbana-Champaign

Language: English

Topic: Catalytic C–H Functionalization Methods

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: green

Funders: National Institutes of Health, National Institute of General Medical Sciences

Awards: G1921871789, G2223967233, Mechanism and Rational Development of Catalytic Carbon-Carbon Bond-Forming Reacti, Transition Metal-Catalyzed, Asymmetric Allylic Borylation and Silylation