Ketyl radicals were produced from ketones by photochemical electron transfer and subsequent proton transfer from tertiary amines. These radicals were stereoselectively added to (5R)-5-(-)-menthyloxy-2[5H]-furanone 1. Due to their low reactivity, the alpha -aminoalkyl radicals which were generated at the same time were not added to 1. The ketones were used in stoichiometric quantities. (C) 2001 Elsevier Science Ltd. All rights reserved.