Regio-, Diastereo-, and Enantioselective Synthesis of Vicinal Diolsvia ?-Silyl Ketones
作者:Dieter Enders、Shiro Nakai
DOI:10.1002/hlca.19900730704
日期:1990.10.31
diastereo-, and enantioselective synthesis of vicinal diols s-trans-4, s-trans-5, and s-cis-4 is described. Symmetrical ketones are converted into their SAMP-or RAMP-hydrazones which are then silylated with (isopropyloxy)dimethylsilyl chloride, followed by ozonolysis to afford the α-silyl ketones (R)-2 of high enantiomeric purity (ee 90– ≥ 98%). On the other hand, methyl ketones, after conversion
描述了一种新的通用有效的邻域二醇s- trans - 4,s- trans - 5和s- cis - 4的区域,非对映和对映选择性合成方法。将对称的酮转化为其SAMP或RAMP hydr,然后将其与(异丙氧基)二甲基甲硅烷基氯进行甲硅烷基化,然后进行臭氧分解,以提供对映体纯度高的α-甲硅烷基酮(R)-2(ee 90–≥98%) 。另一方面,甲基酮在转化为相应的(-)-(S)-1-氨基-2-(甲氧基甲基)吡咯烷(SAMP)hydr之后,被甲硅烷基化,然后用RI烷基化,得到不对称的α-甲硅烷基酮(S)-3具有高对映体纯度(ee 90-≥98%)。上述与L-得到的α -甲硅烷基酮的还原Selectride,随后由CSI键的氧化裂解产生了S-反式-4 - ,仲-反式- 5,和S-顺式- 4具有高非对映选择性(95日-≥98%)且没有消旋作用(ee≥90–≥98%)。