Syntheses of derivatives of L-daunosamine and its C-3 epimer employing as the key step the asymmetric conjugate addition of a homochiral lithium amide to tert-butyl (E,E )-hexa-2,4-dienoate
作者:Stephen G. Davies、G. Darren Smyth、Ann M. Chippindale
DOI:10.1039/a907017f
日期:——
The highly diastereoselective asymmetric conjugate addition of lithium (R)-N-benzyl-α-methylbenzylamide to methyl or tert-butyl (E,E)-hexa-2,4-dienoate, followed by osmium tetroxide-catalysed dihydroxylation of the resulting adducts, provides a concise route to methyl L-daunosaminide hydrochloride and methyl 3-epi-D-daunosaminide hydrochloride, a strategy which is applicable to the synthesis of either
锂(R)-N-苄基-α-甲基苄基酰胺的高度非对映选择性不对称共轭加成至(E,E)-己二酸-6,2-二烯酸叔丁酯或叔丁基,然后四氧化os催化所得加合物的二羟基化,提供了获得甲基L-柔红酰胺盐酸盐和甲基3- epi - D的简洁途径-达柔诺胺盐酸盐,该策略适用于这些化合物的任一对映异构体的合成。关键的二羟基化反应的选择性可以通过采用Sharpless不对称二羟基化方案来显着提高。由于低选择性或需要过多的步骤,使用碘代内酯化或碘代环氨基甲酸酯化反应作为关键步骤的可能替代策略被发现不太令人满意。