An unexpectedly mild thermal Alder-ene-type cyclization of enallenes.
A mild, thermal Alder-ene reaction of enallenes has been developed. The allenic double bond acts as the "ene" and generates a carbon-carbon bond to an unactivated olefinic "enophile" in DMF at 120 degrees C to give [n.3.0] bicyclic systems (n = 3-5) in good yields. Except for a minor [2 + 2] cycloaddition byproduct, the reaction proceeded with complete atom economy, as there is no requirement of a catalyst or additional reactants, and no waste products are formed in the process.
Närhi
Katja
K
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
Franzén
Johan
J
Bäckvall
Jan-E
JE