Method of preparing stereospecific nitroaldols
    8.
    发明授权
    Method of preparing stereospecific nitroaldols 失效
    制备立体特异性硝基醛的方法

    公开(公告)号:US4933505A

    公开(公告)日:1990-06-12

    申请号:US229009

    申请日:1988-08-05

    CPC classification number: C07D309/12 C07C201/12

    Abstract: A method of controlling the diastereoselectivity of the nitroaldol reaction by the use of titanium, zirconium and aluminum based Lewis acids is disclosed. In a preferred embodiment, the reaction of lithium nitronate anion with aldehydes in THF/CH.sub.2 Cl.sub.2 at reduced temperature in the presence of isopropoxy titanium trichloride (TiCl.sub.3 (OPr.sup.i)) yields nitro alcohols enriched in the erythro diastereomer. Erythro-threo ratios of 11.2:1-3.4:1 for aromatic aldehydes and 3.8:1-1:1 for aliphatic aldehydes are typically obtained.

    Abstract translation: 公开了通过使用钛,锆和铝的路易斯酸来控制硝基醛醇反应的非对映选择性的方法。 在一个优选的实施方案中,在异丙氧基三氯化钛(TiCl 3(OPri))存在下,在降低的温度下,在硝酸锂阴离子与醛在THF / CH 2 Cl 2中的反应产生富含赤式非对映异构体的硝基醇。 通常可以获得芳族醛的11.2:1-3.4:1和脂肪醛的3.8:1-1:1的红外 - 苏比。

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