Synthesis of optically active trifluoromethylated indolizidine derivatives via stereoselective radical cyclization.

[reaction: see text]. Asymmetric Michael reaction of lithiated trifluoroacetone SAMP-hydrazone with alkylidenemalonates gave addition products stereoselectively. Hydrolyzed enantiomerically pure ketoacids were cyclized to dihydropyridinones. N-Iodopropylation followed by radical cyclization gave optically active trifluoromethylated indolizidinones stereoselectively.