(Z)-3-Alkylidene-4,5-dihydro-4-hydroxy-5-methyl-2-(3H)-furanones by Regio- and Diastereo-selective Ene Reaction of Singlet Oxygen (Schenk Reaktion) with γ-Hydroxy Vinylstannanes: An Enantioselective Synthesis of Dihydromahubanolide B - Adam, Waldemar; Klug, Peter (Synthesis, 1994)