作者:Dieter Seebach、Albert K. Beck、Triptikumar Mukhopadhyay、Elizabeth Thomas
DOI:10.1002/hlca.19820650402
日期:1982.6.16
Three methods are described by which diastereomerically enriched nitroaldols and their O-silylated derivatives can be prepared. threo-Nitroaldols prevail up to 10:1 over the erythro-isomers if doubly deprotonated nitroaldols 28 are quenched with acetic acid (THF/HMPT or DMPU, − 100°) (see Scheme 5 and Table 2). O-Trimethyl- or O-(t-butyl)dimethylsilylated (TBDMSi) erythro-nitroaldols can be obtained
描述了三种可以制备非对映体富集的硝基醛醇及其O-甲硅烷基化衍生物的方法。如果用乙酸(THF / HMPT或DMPU,− 100°)淬灭双去质子化的硝基醛醇28,则苏式硝基硝基苯酚比赤型异构体占10:1 (参见方案5和表2)。ø -三甲基-或ø - (吨丁基)dimethylsilylated(TBDMSi)赤-nitroaldols可以由相应的锂nitronates的质子化(获得35,39)在THF中在低温下(参见方案6和7)。所述赤- ö也形成在氟化物催化加成TBDMSi-nitronates的(-TBDMSi-硝基醛醇衍生物40-45)醛(参见方案8和9),在后者的反应没有1,2-不对称诱导观察到如果一个支化silylnitronates或醛采用(参见48/49和50/51) -导致反应的立体化学过程赤- ö -TBDMSi-nitroaldols如下广泛的适用性的拓扑规则(参见方案10);