Glycosylated vinyl ethers by the Julia–Lythgoe–Kocienski olefination: application to the synthesis of 2′,5′-dideoxydisaccharides and carbohydrated β-lactams
作者:Iván Pérez Sánchez、Edward Turos
DOI:10.1016/j.tetasy.2009.05.039
日期:2009.7
(E)-stereoselectivities. These glycosylated adducts undergo hetero-Diels–Alder reactions with 2-formyl-1-malondialdehyde to afford 2′,5′-dideoxygenated disaccharides in good yields and complete regio- and endo-selectivity. Alternatively, the [2+2]-cycloaddition reaction of the glycosidic enol ethers with chlorosulfonyl isocyanate provided glycosylated β-lactams regioselectively and with only trans-stereoselectivity
Julia-Lythgoe-采用了五步序列由市售的d-(-)-核糖,d-(+)-半乳糖和d-(+)-葡萄糖制备的α-吡啶基砜。 Kocienski与醛的烯化反应。在室温下使用固体KOH的这一一锅法操作方案,以中等至极好的收率和(E)-立体选择性提供了相应的糖苷烯醇醚。这些糖基化的加合物与2-甲酰基-1-丙二醛进行异Diels-Alder反应,以高产率提供2',5'-二脱氧二糖,并具有完全的区域和内选择性。或者,糖苷烯醇醚与氯磺酰基异氰酸酯的[2 + 2]-环加成反应选择性地提供了糖基化的β-内酰胺,只有反式-立体选择性。β-内酰胺类可以转化为N-甲硫基衍生物,对金黄色葡萄球菌耐甲氧西林菌株显示出良好的抗菌活性。