Total Syntheses of (±)-Dracocephalone A and (±)-Dracocequinones A and B.
Angew Chem Int Ed Engl
; 61(46): e202210821, 2022 11 14.
Article
in En
| MEDLINE
| ID: mdl-36121442
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.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Lewis Acids
Language:
En
Journal:
Angew Chem Int Ed Engl
Year:
2022
Document type:
Article
Affiliation country:
United States