1. Total Syntheses of (±)-Dracocephalone A and (±)-Dracocequinones A and B
- Author
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Taehwan Hwang, Joseph P. Tuccinardi, Alexandra A. Beard, Amy C. Jackson, Min J. Jung, and John L. Wood
- Subjects
Cycloaddition Reaction ,Stereoisomerism ,General Chemistry ,General Medicine ,Oxidation-Reduction ,Catalysis ,Lewis Acids - Abstract
Described herein are the first total syntheses of (±)-dracocephalone A (1) and (±)-dracocequinones A (4) and B (5). The synthesis was initially envisioned as proceeding through an intramolecular isobenzofuran Diels-Alder reaction, a strategy that eventually evolved into a Lewis acid-promoted spirocyclization. This highly diastereoselective transformation set the stage for trans-decalin formation and a late-stage Suárez oxidation that produced a [3.2.1] oxabicycle suited for conversion to 1. Brønsted acid-mediated aromatization, followed by a series of carefully choreographed oxidations, allowed for rearrangement to a [2.2.2] oxabicycle poised for conversion to 4 and 5.
- Published
- 2022