M. Versteeg et al., THE FIRST ENANTIOSELECTIVE SYNTHESIS OF ISOFLAVONOIDS - (R)-ISOFLAVANS AND (S)-ISOFLAVANS, Journal of the Chemical Society, Chemical Communications, (13), 1995, pp. 1317-1318
alpha-Benzylation of (+)- and (-)-N-phenylacetyl imidazolidinones with
2-O-methoxymethylbenzyl bromide, followed by reductive removal of the
chiral auxiliary and cyclization, leads to isoflavans in excellent en
antiomeric excess and yield.