The five-membered ring building blocks 2+3 are enantioselectively produced by conjugate addition of a chiral ligand-modified organocuprate to 2-methylcyclopent-2-enone (1) (chemical yield: 88%; e.e.: 88%) and successfully converted in a multi-step sequence, after final enantioselection by recrystallization of an appropriate intermediate, into the pseudoguaianolide (+)-confertin (5).
QUINKERT, GERHARD;SCHMALZ, HANS-GUNTHER;WALZER, EGON;GROSS, STEFAN;KOWALC+, LIEBIGS ANN. CHEM.,(1988) N 4, 283-315