Generation and trapping of alkene radical cations under nonoxidizing conditions: formation of six-membered rings by exo- and endo-mode cyclizations.
[reaction: see text] It is demonstrated that alkene radical cations generated by the radical ionic fragmentation of beta-(phosphatoxy)alkyl radicals undergo efficient nucleophilic capture by amines in either the 6-exo or 6-endo modes, leading to six-membered nitrogen heterocycles. Suitable placement of an alkene enables the juxtaposition of a radical cyclization resulting in the formation of both the indolizidine and 1-azabicyclo[3.2.1]octane skeleta.
Crich
David
D
Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA. dcrich@uic.edu
Neelamkavil
Santhosh
S