Synthesis of both enantiomers of flavanone and 2-methylchromanone

Article abstract of DOI:10.1002/1522-2675(200210)85:10<3473::AID-HLCA3473>3.0.CO;2-7

An efficient enantiospecific synthesis of the (R)- and (S)-enantiomers of flavanone and 2-methylchromanone is described. The key steps are a C,C-bond formation by ring opening of a chiral epoxide with a dithiane anion, followed by a Mitsunobu cyclization. The products obtained have high enantiomeric purity.