A diastereoselective formal synthesis of berkelic acid.
A formal synthesis of berkelic acid is reported. The strategy employs the combination of a chiral exocyclic enol ether and an achiral isochromanone to afford the chroman spiroketal core via a base-triggered generation and cycloaddition of an o-quinone methide intermediate. Other key steps include equilibration of the spiroketal, intramolecular benzylic oxidation, and lactone addition/hemiketal reduction; all occur with good diastereoselectivity.
Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106-9510, United States.
Todd A
TA
Wenderski
Maurice A
MA
Marsini
Thomas R R
TR
Pettus
D003500:Cyclization; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013141:Spiro Compounds / Q000138:chemical synthesis*; D013237:Stereoisomerism
D013141:Spiro Compounds; C520589:berkelic acid