Efficient syntheses of (+/-)-hydrangenol, (+/-)-phyllodulcin and (+/-)-macrophyllol

In this paper we report on a efficient and flexible synthetic route towards the total syntheses of the dihydrocoumarine derivatives hydrangenol (1), phyllodulcin (1a) and macrophyllol (6b). The syntheses started with a readily available phosphonium salt 2 and suitable modified benzaldehydes 3/3a/3b resulting in 46 to 61% overall yields in three to four-steps sequences. The racemic products could be separated by chiral HPLC. The evidence of the(R)-enantiomer for sweetness could be demonstrated for la. (C) 2003 Elsevier Ltd. All rights reserved.