Process for preparing enantiomer-enriched cyanohydrins in which an acetal or ketal of the formula (I) is reacted
1
where
R1 and R2 independently of one another are an unsubstituted or substituted C
1
-C
20
-alkyl, C
5
-C
20
-aryl or C
5
-C
20
-heteroaryl radical,
or one of the two radicals is hydrogen, or R1 and R2 together form an unsubstituted or substituted C
2
-C
20
-alkylene radical,
and R3 and R4 independently of one another can be an unsubstituted or substituted C
1
-C
20
-alkyl, C
5
-C
20
-aryl, C
5
-C
20
-heteroaryl, C
7
-C
20
-alkylaryl, C
5
-C
20
-alkyl heteroaryl or C
5
-C
20
-aralkyl radical or an unsubstituted or substituted C
5
-C
20
-heterocycle or C
5
-C
20
-alkyl heterocycle or together can be an unsubstituted or substituted C
4
-C
20
-alkylene radical which can contain one or more heteroatoms in the chain, or one of the radicals is hydrogen,
in the presence of an (R)- or (S)-hydroxynitrile lyase and a cyanide group donor in an organic, aqueous or two-phase system or in emulsion at −5 to +40° C. to give the corresponding enantiomer-enriched cyanohydrins of the formula (II),
2
where
R3 and R4 are as defined above.
制备对映体富集的
氰醇的过程中,以式(I)的
缩醛或
缩酮为反应物,其中R1和R2独立地是未取代或取代的C1-C20烷基,C5-C20芳基或C5-C20杂芳基基团,或其中之一为氢,或R1和R2共同形成未取代或取代的C2-C20烷基基团,而R3和R4独立地可以是未取代或取代的C1-C20烷基,C5-C20芳基,C5-C20杂芳基,C7-C20烷基芳基,C5-C20烷基杂芳基或C5-C20-烷基芳基基团或未取代或取代的C5-C20杂环或C5-C20烷基杂环,或者一起可以是未取代或取代的C4-C20烷基基团,其中可以在链中含有一个或多个杂原子,或其中之一为氢,在有机、
水性或两相体系或乳液中,在-5至+40℃下,在(R)-或(S)-羟基腈酶和
氰基供体的存在下,得到相应的对映体富集的式(II)的
氰醇,其中R3和R4如上所定义。