Diastereo- and Enantioselective Synthesis of α,α′-Disubstituted,<i>C</i>
<sub>2</sub>-Symmetric Ketones Using the SAMP-/RAMP-Hydrazone Method
作者:Dieter Enders、Winfried Gatzweiler、Udo Jegelka
DOI:10.1055/s-1991-28405
日期:——
Starting from simple, symmetric ketones such as, 3-pentanone,1, 3-diphenyl-2-propanone and 2,2-dimethyl-1,3-dioxan-.5-one, α,α′-bisalkylation of the corresponding SAMP-hydrazones (S)-2 and (S)-8 [(S)-1-(alkylideneamino)-2-(methoxymethyl)pyrrolidines and (S)-1-(2,2-dimethyl-1,3-dioxan-5-ylideneamino)-2-(methoxymethyl)pyrrolidines, respectively], followed by oxidative cleavage with ozone affords chiral, C2-symmetric ketones 5 and (S,S)-11 of high diastereo- and enantiomeric purity (de, ee > 98%).
从简单的对称酮开始,如 3-戊酮、1, 3-二苯基-2-丙酮和 2,2-二甲基-1,3-二氧杂环戊酮。5-酮,相应的 SAMP-hydrazones (S)-2 和 (S)-8 [(S)-1-(亚烷基氨基)-2-(甲氧基甲基)吡咯烷和 (S)-1-(2,2-二甲基-1,3-二氧杂环戊烯-5-亚烷基氨基)-2-(甲氧基甲基)吡咯烷的δ、δ′-双烷基化、 分别],然后用臭氧进行氧化裂解,得到手性 C2 对称酮 5 和(S,S)-11,它们的非对映纯度和对映纯度都很高(de、ee > 98%)。