A Stereocontrolled, Efficient Synthetic Route to Bioactive Sphingolipids: Synthesis of Phytosphingosine and Phytoceramides from Unsaturated Ester Precursors via Cyclic Sulfate Intermediates
作者:Linli He、Hoe-Sup Byun、Robert Bittman
DOI:10.1021/jo001225v
日期:2000.11.1
4-O-protected (E)-alpha,beta-unsaturated ester 5 (generated by dihydroxylation of 1-hexadecene, followed by oxidation to the aldehyde and Horner-Wadsworth-Emmons olefination), (ii) conversion to cyclic sulfate intermediate 7, and (iii) regioselective alpha-azidation of 7. Reduction of 4-O-protected 2-azido ester 8 via alpha-azidolactone 9 afforded phytosphingosine 1a. Staudinger reduction of the azido
已经开发了一种高效且高度对映选择性的方法,用于制备D-核糖和L-lyxo-植物鞘氨醇(分别为1a,b)和植物神经酰胺(2a,b)。合成的关键步骤如下:(i)4-O保护的(E)-α,β-不饱和酯5的催化不对称二羟基化反应(通过1-十六碳烯的二羟基化反应,然后氧化成醛而生成) (Horner-Wadsworth-Emmons烯化反应),(ii)转化为环状硫酸盐中间体7和(iii)7的区域选择性α-叠氮反应。通过α-叠氮内酯9还原4-O-保护的2-叠氮基酯8得到了植物鞘氨醇1a 。施陶丁格还原8位叠氮基,然后在水性介质中原位N-酰化并用NaBH(4)/ LiBr还原酯官能度,从而提供了植物神经酰胺2a。通过使用类似的方法,合成了植物鞘氨醇1b。通过环硫酸盐中间体15以高产率从1-十六醇合成D-赤藓醇4、5-二氢鞘氨醇1c和D-赤藓醇4,5-二氢神经酰胺2c。C-2,C-3和C的所需构型通过本