290
2
General Synthetic Methods
⊡ Scheme 21
3.1.2 Exocyclic Epoxides
These compounds are conveniently obtained by epoxidation of the exocyclic double bond in
the sugar skeleton. Such oxidation with m-chloroperbenzoic acid (MCPBA) usually proceeds
with moderate selectivity. Treatment of homologated galactose 73 with MCPBA afforded both
epoxides 74 and 75 in a 3:1 ratio; these compounds are synthons for the preparation of antibiotic olguinine ( > Scheme 22) [1].
⊡ Scheme 22
2
General Synthetic Methods
⊡ Scheme 21
3.1.2 Exocyclic Epoxides
These compounds are conveniently obtained by epoxidation of the exocyclic double bond in
the sugar skeleton. Such oxidation with m-chloroperbenzoic acid (MCPBA) usually proceeds
with moderate selectivity. Treatment of homologated galactose 73 with MCPBA afforded both
epoxides 74 and 75 in a 3:1 ratio; these compounds are synthons for the preparation of antibiotic olguinine ( > Scheme 22) [1].
⊡ Scheme 22