β-Rhamnosides from 6-thio mannosides.
Upon condensation of 6-thio-6-deoxy-mannosyl donors 1,2-cis products are obtained with a high degree of stereoselectivity. Subsequent reductive removal of the 6-thio functionality gives 1,2-cis rhamnosides. The 1,2-cis-selectivity can be rationalized with a product forming (3)H(4)-oxocarbenium, which is in equilibrium with a bridged sulfonium intermediate.
Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
Alphert E
AE
Christina
Daan
D
van der Es
Jasper
J
Dinkelaar
Hermen S
HS
Overkleeft
Gijsbert A
GA
van der Marel
Jeroen D C
JD
Codée