An efficient synthesis of optically active (2R, 3R)-2-methyl-3-[(1R)-1-methylprop-2-enyl] cyclopentanone, a useful chiral building block for synthesis of vitamin D and …
An efficient synthesis of optically active (2R, 3R)-2-methyl-3-[(1R)-1-methylprop-2-enyl] cyclopentanone, a useful chiral building block for synthesis of vitamin D and steroids, has been developed starting from readily accessible optically active secondary propargyl phosphate (R)-2, where the asymmetric Michael addition of a chiral allenyltitanium to alkylidenemalonate 3 is a key reaction.