报道一种合成天然氮杂糖L-deoxygulojirimycin关键中间体及全保护L-gulono-1,5-lactam的方法.其关键反应之一为二碘化钐(SmI2)促进下对硅基保护的3-羟基戊二酰亚胺10的C-2位的区域和立体选择性不对称羟甲基化,区域选择性为80 20,立体选择性为93 7;另一关键反应为采用OsO4-NMO体系对18进行不对称双羟基化反应,立体选择性单一,并通过NOE确定产物的立体化学.The paper reported a convenient asymmetric synthesis of a new intermediate for the asymmetric synthesis of aza-sugar L-deoxygulojirimycin and its δ-lactam using a chiral building block developed recently in this laboratory.One of the key steps involved the SmI_2 mediated C-2 regio(ratio of C-2/C-6 addition = 8020) selective hydroxymethylation of the TBS protected 3-hydroxyglutarimide 10 with chloromethyl benzyl ether,followed by debenzylation and highly cis-diastereoselective reductive deoxygenation(ds = 937).After successive O-silylation,treatment of lactam 11 with LDA and phenylselenium bromide yielded α-phenylselenide derivative of 11,which was subjected to H_2O_2 oxidation to give directly 18.The other key step is a highly trans-diastereoselective dihydroxylation of compound 18 with OsO_4-NMO system in a mixed solvent system to give 12 as the only isolable product,which could be easily converted via deprotection or reduction to azasugar 5 and other analogous according to the known procedures.The stereochemistry of the dihydroxylated product 12 was determined by NOESY technique.国家自然科学基金(2039005020572088)资
