Synthesis of (+)-(R)-5-hydroxy-6-hydroxymethyl-7-methoxy-8-methylflavanone

The synthesis of (+)-(R)-5-hydroxy-6-hydroxymethyl-7-methoxy-8-methylflavan one is described. A new chromylation method of beta-ketosulfoxide 9 leading to the Michael acceptor 12 has been developed. Dilithium tetrachlorocuprat e was shown to be a very efficient catalyst for the conjugate addition reac tion of phenyl magnesium bromide to the alpha,beta-unsaturated sulfoxide 12 . The instability of the obtained adducts 10 represents a limitation in ter ms of yield. It was confirmed that the natural flavanone leridol does not p ossess the structure of title compound 1. (C) 1999 Elsevier Science Ltd. Al l rights reserved.