Concentration dependence of the sharpless asymmetric amidohydroxylation of isopropyl cinnamate
[reaction: see text]A need to prepare large quantities of phenylisoserine for the semisynthesis of paclitaxel prompted us to examine the Sharpless amidohydroxylation reaction to see if it could be run at concentrations greater than those reported in the literature. During these investigations, we discovered that the amount of amidoalcohol produced in the reaction decreased while the diol side product increased as the concentration increased. We discovered that acetamide suppresses this side reaction and allows us to run the chemistry at 0.1 g/mL rather than the 0.014 g/mL reported in the literature.
Wuts
PG
Chemical Process Research and Development, Pharmacia, Kalamazoo, Michigan 49001, USA. peter.g.wuts@am.pnu.com
Anderson
AM
Goble
MP
Mancini
SE
VanderRoest
RJ