Development of an intramolecular aryne ene reaction and application to the formal synthesis of (±)-crinine.
A general and high yielding annulation strategy for the synthesis of various carbo- and heterocycles, based on an intramolecular aryne ene reaction is described. It was found that the geometry of the olefin is crucial to the success of the reaction, with exclusive migration of the trans-allylic-H taking place. Furthermore, the electronic nature of the aryne was found to be important to the success of the reaction. Deuterium labeling studies and DFT calculations provided insight into the reaction mechanism. The data suggests a concerted asynchronous transition state, resembling a nucleophilic attack on the aryne. This strategy was successfully applied to the formal synthesis of the ethanophenanthridine alkaloid (±)-crinine.
Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
David A
DA
Candito
Dennis
D
Dobrovolsky
Mark
M
Lautens
D047151:Amaryllidaceae Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry*; D008958:Models, Molecular; D013237:Stereoisomerism
D047151:Amaryllidaceae Alkaloids; C528221:crinine