title: Total synthesis of cephalosporolide E via a tandem radical/polar crossover reaction. The use of the radical cations under nonoxidative conditions in total synthesis.
abstract: The present work reports the first example of the use of the chemistry of radical cations under nonoxidative conditions in total synthesis. Using a late-stage tandem radical/polar crossover reaction, a highly stereoselective total synthesis of cephalosporolide E (which is typically obtained admixed with cephalosporolide F) was accomplished. The reaction of a phthalimido derivative with triphenyltin radical in refluxing toluene engenders a contact ion-pair (radical cation) that leads, in the first instance, to the cephalosporolide F, which is transformed into the cephalosporolide E via a stereocontrolled spiroketal isomerization promoted by the diphenylphosphate acid that is formed during the tandem transformation.
authors: Centro de Investigación de la Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla (BUAP) , 14 Sur Esq. San Claudio, Col. San Manuel, 72570, Puebla, México.
authors: Omar
authors: O
authors: Cortezano-Arellano
authors: Leticia
authors: L
authors: Quintero
authors: Fernando
authors: F
authors: Sartillo-Piscil