CATALYTIC ASYMMETRIC IODOCARBOCYCLIZATION REACTION OF 4-ALKENYLMALONATES AND ITS APPLICATION TO ENANTIOTOPIC GROUP SELECTIVE REACTION

The iodocarbocyclization reaction of 4-alkenylmalonate derivatives pro ceeded with excellent enantioselectivity (greater than or equal to 95% ee) in the presence of 10-40 mol % of Ti(TADDOLate)(2). The Ti(TADDOL ate)(2)-mediated catalytic asymmetric reaction was extended to the ena ntiotopic group selective reaction of bisalkenylated malonates, giving rise to trisubstituted cyclopentanoid compounds with both high diaste reoselectivity (86-94% de) and excellent enantioselectivity (greater t han or equal to 95% ee). An efficient synthesis of (+)-boschnialactone from the product of the present reaction was also achieved.