Total syntheses of the angucyclinone antibiotics (+)-emycin A and (+)-ochromycinone

The first asymmetric synthesis of the angucyclinone antibiotics, emycin A and ochromycinone, is achieved via a short, efficient sequence from 5-hydroxy-1,4-naphthoquinone with the key step being an effective kinetic resolution of a racemic diene in a Diels–Alder reaction promoted by a chiral Lewis acid derived from (S)-3,3′-diphenyl-1,1′-biaphthalene-2,2′-diol.