Enantioselective Synthesis of (−)‐Halenaquinone

Abstract

The efficient, 12-14 step (LLS) total synthesis of (-)-halenaquinone has been achieved. Key steps in the synthetic sequence include: (a) proline sulfonamide-catalyzed, Yamada-Otani reaction to establish the C6 all-carbon quaternary stereocenter, (b) multiple, novel palladium-mediated oxidative cyclizations to introduce the furan moiety, and (c) oxidative Bergman cyclization to form the final quinone ring.

Visible-Light-Promoted Multistep Tandem Reaction of Vinyl Azides toward the Formation of 1-Tetralones

“…Tetralone is the core skeleton of many biologically active molecules, which is also widely present in natural products and drugs, − such as Picropodophyllon with antiviral activity, Halenaquinone with antitumor activity, etc. as listed in Scheme .…”

Pummerer Cyclization Revisited: Unraveling of Acyl Oxonium Ion and Vinyl Sulfide Pathways

“…We synthesized a series of enantiomerically enriched polycyclic scaffolds utilizing an asymmetric Yamada–Otani cyclization developed in our laboratory − to explore their potential utility in the Pummerer cyclization (see Supporting Information). With the necessary sulfoxides in hand, we selected sulfoxide 7a as the prototypical example to explore its reactivity (Table ).…”

Dynamic Kinetic Asymmetric Transformation of Racemic Diastereomers: Diastereo‐ and Enantioconvergent Michael–Henry Reactions to Afford Spirooxindoles Bearing Furan‐Fused Rings

“…[2a, 4-6] Furan-fused ring systems, in which at least two rings are fused with the furan ring, are present in enzyme inhibitors and other biofunctional natural products. [7] Therefore, we sought strategies for the synthesis of spirooxindoles bearing furan-fused ring systems. We designed a route starting from the reaction of oxindole-derived enones 1 with 1,3-cyclohexanediones 2 to form 1,4-diketone derivatives 3 (Scheme 1).…”