Access to iminosugars by aldol additions of metalated bis-lactim ethers to L-erythrose derivatives

Aldol additions of metalated bis-lactim ethers derived from cyclo-[Gly-D-Val] 3A-E* to mismatched L-erythrose-derivatives 4a and 4b have been studied. Reactions of titanium(IV) and tin(II) azaenolates with the lactol derivative 4b allow direct and moderate (syn,syn)- or highly (anti,anti)-selective access to polyhydroxy amino acids that have been efficiently transformed into 1-deoxy-D-gulonojirimycin or 1-deoxy-D-allonojirimycin. (C) 2002 Elsevier Science Ltd. All rights reserved.