(Chemical Equation Presented) The kinetic resolution of racemic cis-4-phenyl- and cis-4-tert-butyl-3-hydroxy-β-lactam derivatives with 7-O-triethylsilylbaccatin III yielded paclitaxel and butitaxel analogues with high diastereoselectivity. The results demonstrated that the tert-butyldimethylsilyl protecting group at the C3-hydroxy group of the β-lactams provided optimum kinetic resolution in comparison with the sterically less demanding triethylsilyl group and the larger triisopropylsilyl group. In addition, it was found that the C4 β-lactam substituents also influenced diastereoselectivity. The C4 tert-butyl-β-lactams provided better diastereoselectivity than the corresponding C4 phenyl β-lactams.
|Number of pages||4|
|Journal||Journal of Organic Chemistry|
|State||Published - Feb 2 2007|