Stereoselective Synthesis of 4-Substituted 2,4-Dichloro-2-butenals by α- and γ-Regioselective Double Chlorination of Dienamine Catalysis
作者:Satoru Arimitsu、Kazuto Terukina、Tatsuro Ishikawa
DOI:10.1055/s-0037-1609559
日期:2018.9
multireactive 1,3-dichloro allylic unit useful for the construction of Z-vinyl chlorides; the chloride on the allylic position was replaced with mild nucleophiles such as MeOH and EtOH via an SN2 substitution reaction, and its aldehyde moiety was used as a synthetic handle and transformed into an alcohol or a vinyl group. All products obtained after those synthetic manipulations maintained excellent diastereoselectivities
L-脯氨酸催化的可烯醇化 α,β-不饱和醛与 N-氯琥珀酰亚胺 (NCS) 反应得到相应的 4-取代 2,4-二氯-2-丁烯醛,产率适中,非对映选择性 (Z/E = >20 /1) 通过在二烯胺中间体的 α- 和 γ- 位连续双氯化。相应的 2,4-二氯-2-丁烯醛含有多反应性 1,3-二氯烯丙基单元,可用于构建 Z-氯乙烯;烯丙基位置的氯化物通过SN2取代反应被温和的亲核试剂如MeOH和EtOH取代,其醛部分用作合成手柄并转化为醇或乙烯基。在这些合成操作后获得的所有产品都保持了出色的非对映选择性 (Z/E = >20/1)。