Highly diastereoselective addition of photochemically generated radicals to (5R)-(−)-menthyloxy-2[5H]-furanone - synthesis of(−)-terebic acid

Photochemically generated ketyl and 2-dioxolanyl radicals are added with high diastereoselectivity (de > 95%) to (5R)-(−)-5-menthyloxy-2[5H]-furanone. This reaction is used for the asymmetric synthesis of (−)-terebic acid. The double bond is attacked by the radicals on the ul-side.