O- and S-Nucleophiles including galactose, serine and cysteine derivatives undergo MICHAEL-type additions to hex-1-en-3-uloses to furnish stereoselectively the α-2-deoxy-ulosides. The keto function at C-3 can be reduced stereoelectively with NaBH4. Both configurations can be obtained depending on the presence or absence of CeCl3. Glycosylation takes place either base catalyzed with DBU (1,8-diazabicyclo[5
包括半
乳糖,
丝氨酸和半胱
氨酸衍
生物在内的O-和S-Nucleophiles经过对hexa-1-en-3-ulose进行MICHAEL型加成,以立体选择性地提供α-2-deoxy-ulosides。用NaBH 4可以选择性地降低C-3处的酮基功能。取决于CeCl 3的存在与否,可以获得两种配置。糖基化发生在
DBU(
1,8-二氮杂双环[5.4.0]十一碳-7-烯)催化的碱或KCN / 18-crown-6或ZnI 2催化的酸中。