Synthesis of a Polymer-Bound Galactosylamine and Its Application as an Immobilized Chiral Auxiliary in Stereoselective Syntheses of Piperidine and Amino Acid Derivatives
作者:Gernot Zech、Horst Kunz
DOI:10.1002/chem.200400253
日期:2004.9.6
The azide was reduced to the corresponding galactopyranosylamine, which served as a versatile chiral auxiliary in highly diastereoselective Ugi four-component condensation reactions at ambient temperature. Fluoride-induced cleavage from the polymeric support furnished N-glycosylated N-acylated alpha-amino acid amides. The reaction of the immobilized galactosylamine with aldehydes gave rise to the corresponding
合成了在半乳糖的C-6位带有羟基官能化的间隔单元的2,3,4-三-O-多聚戊二酰化的β-D-吡喃半乳糖叠氮化物,并通过使用聚合物结合的氯硅烷将其固定在固相上。叠氮化物被还原为相应的吡喃半乳糖苷,在环境温度下,它在高度非对映选择性的Ugi四组分缩合反应中作为通用的手性助剂。氟化物诱导的从聚合物载体上的裂解提供了N-糖基化的N-酰化的α-氨基酸酰胺。固定的半乳糖胺与醛的反应产生相应的醛亚胺,其在室温下与Danishefsky's二烯进行多米诺骨牌曼尼希-迈克尔缩合反应,在固相上生成2-取代的5,6-二氢哌啶-4-酮。随后用四正丁基氟化铵裂解可得到高收率,纯度和非对映选择性的N-糖基化产物。在疏松的嗜氧性路易斯酸甲基铝[双(2,6-二叔丁基-4-甲基苯氧基)]存在下,将化学选择性的1,4-氢化物加到与聚合物结合的脱氢哌啶酮上。将氰基改性的吉尔曼试剂共轭加成到固定的脱氢哌啶子酮上,提供了2,6-顺