Asymmetric Total Synthesis of (-)-Podophyllotoxin

Article abstract of DOI:10.1021/ja00231a041

Using a diastereoselective addition of the appropriate aryllithium to a naphtalene-containing chiral oxazoline leads to advanced intermadiate 11 in the podophyllotoxin series.The latter is obtained in a 92:8 de.Transformation of the oxazoline moiety to the requisite lactone 18 followed by invoking the Kende route to the target gave natural (-)-podophyllotoxin in 94 percent ee.The overall yield of the sequence, accomplished in 24 steps, was 5 percent.