Asymmetric Syntheses of Methyl <i>N</i>,<i>O</i>-Diacetyl-<scp>d</scp>-3-<i>epi</i>-daunosaminide and Methyl <i>N</i>,<i>O</i>-Diacetyl-<scp>d</scp>-ristosaminide
作者:Kristína Csatayová、Stephen G. Davies、J. Gair Ford、James A. Lee、Paul M. Roberts、James E. Thomson
DOI:10.1021/jo4020563
日期:2013.12.20
Ab initio asymmetric syntheses of methyl N,O-diacetyl-d-3-epi-daunosaminide and methyl N,O-diacetyl-d-ristosaminide, employing diastereoselective epoxidation and dihydroxylation, respectively, of alkyl (3S,αR,Z)-3-[N-benzyl-N-(α-methylbenzyl)amino]hex-4-enoates as the key steps, are reported. The requisite substrates were readily prepared using the conjugate additions of lithium (R)-N-benzyl-N-(α-methylbenzyl)amide
从头甲基的不对称合成Ñ,ö -diacetyl- d -3-外延-daunosaminide和甲基Ñ,ö -diacetyl- d -ristosaminide,采用非对映选择性环氧化和二羟基化,分别,烷基的(3小号,α - [R ,Ž)报道了作为关键步骤的-3- [ N-苄基-N-(α-甲基苄基)氨基]己-4-烯酸酯。使用锂(R)-N-苄基-N-(α-甲基苄基)酰胺共轭加成到甲基和叔酸上即可轻松制备必要的底物(E)-六-2-烯-4-壬酸丁酯,然后进行非对映选择性炔烃还原。使用OsO 4进行的顺式-二羟基化在空间控制下在烯烃的4 Re,5 Re面上进行,得到相应的二醇,随后对其进行内酯化。同时,在原位形成的铵离子的氢键控制下,在烯烃的相反的4 Si,5 Si面上进行了使用F 3 CCO 3 H和F 3 CCO 2 H的环氧化。用浓H 2 SO 4处理中间环氧化物促进高度区域选择性的开环(与