Preparation of alpha-hydroxy ketones via carbene-catalyzed umpolung reaction of aldehydes
申请人:Jackstell Ralf
公开号:US20080051608A1
公开(公告)日:2008-02-28
The present invention relates to the preparation of α-hydroxy ketones of the general formula I. In particular, the invention relates to novel imidazolinium carboxylate adducts and to a novel process for using catalytic amounts of imidazolium and imidazolinium carboxylate adducts in the acyloin reaction of aldehydes to prepare hydroxy ketones of the general formula I,
where R and R′ are the same or different and are each H or a straight-chain or branched and optionally substituted C
1
-C
12
-alkyl radical, and R″═H
3
CSCH
2
CH
2
, t-butyl, n-butyl, sec-butyl, n-propyl, i-propyl, an optionally heteroatom-substituted C
6
-C
18
-aryl, heteroaryl, C
6
-C
18
-arylalkyl, especially phenylmethyl, where phenyl may again be heteroatom-substituted, or heteroalkyl.
本发明涉及通式I的α-羟基酮的制备。特别是,本发明涉及新型咪唑啉酮酸盐加合物以及一种新的过程,该过程利用咪唑和咪唑啉酮酸盐加合物的催化量在醛的酰乙醇反应中制备通式I的羟基酮,其中R和R′相同或不同,每个都是H或直链或支链且可选择取代的C1-C12烷基基团,而R″=H3CSCH2CH2、叔丁基、正丁基、异丁基、正丙基、异丙基、可选择杂原子取代的C6-C18芳基、杂原子芳基、C6-C18芳基烷基,特别是苯甲基,其中苯可能再次被杂原子取代,或者杂原子烷基。