Enantioselective Synthesis of Hydrobenzofuranones Using an Asymmetric Desymmetrizing Intramolecular Stetter Reaction of Cyclohexadienones
作者:Qin Liu、Tomislav Rovis
DOI:10.1021/op600278f
日期:2007.5.1
A series of cyclohexadienones were synthesized by dearomatization of phenols followed by Dess-Martin oxidation. Asymmetric intramolecular Stetter reactions of these substrates provide hydrobenzofuranones in good to excellent yields and excellent stereoselectivities. Up to three stereocenters as well as quaternary stereocenter are formed from polysubstituted substrates. A scale up experiment demonstrates
Visible-Light-Mediated Facile Reductive Aromatization of Quinols
作者:Leifeng Wang、Zhiming Yan
DOI:10.1055/s-0035-1561404
日期:——
range of phenols bearing multiple useful functionalities at their meta positions were prepared from the corresponding quinols under the cooperative effects of visible light irradiation, Ru(bpy)3Cl2 photosensitizer, Hunig’s base, LiBF4, and MeCN solvent. The process involves visible-light-enabled photocatalytic cleavage of C–O bond as the strategic event.
Catalyst-Controlled Diastereoselective Synthesis of Bridged [3.3.1] Bis(Indolyl)-Oxanes and Oxepanes via Desymmetrization of Bis(Indolyl)-Cyclohexadienones
oxepanes via diastereoselective desymmetrization of bis(indolyl)-cyclohexadienones is presented for the first time. The reaction is highly atom- and step-economic, furnishing sp3-rich functionalized bis(indolyl) derivatives in good to excellent yields with wide substrate scope. The reaction proceeds through Friedel–Crafts alkylation followed by catalyst-controlled selective C–Cbondformation/rearrangement
The cascade difunctionalization of α,β-unsaturated carbonyls by nucleophilic halogenation followed by enolate trapping with other electrophiles is highly challenging in synthetic organic chemistry. Herein, we report a chemo- and diastereoselective cascade annulation of enone-tethered cyclohexadienones by using an unconventional combined Lewisacidcatalyzed halogenation reaction in the presence of
reported for the synthesis of intricate scaffolds from enone-tethered cyclohexadienones and primary amines. This method discloses the base-catalyzed synthesis of highly valued bridged aza-tricyclic frameworks with a high level of product selectivity and stereoselectivity. Gram scale synthesis and synthetic transformation were shown to afford structurally diverse bridged aza-polycyclic amines. Control experiments