Preparation method of axially chiral methylene cyclohexane derivative

Abstract

The invention discloses a preparation method of an axially chiral methylene cyclohexane derivative. The preparation method comprises the following step of: performing an enantioselective hydrosilylation addition reaction on an exoallene compound serving as a raw material under the action of a copper catalyst, a ligand and silane to obtain the axially chiral methylene cyclohexane derivative. According to the invention, the one-step method is adopted, a system is simple, operation is convenient and fast, the axially chiral methylene cyclohexane derivative can be obtained through treatment without secondary conversion, the method is adapted to a wide range of substrates and resistant to various substrates and silane, and the product yield and the enantiomeric excess value of the method are not inferior to the product yield and the enantiomeric excess value of a traditional method. The invention provides a new synthesis means for developing a class of axially chiral methylene cyclohexane derivatives, and the method has economic practicability and industrial application prospects.

Description

technical field [0001] The invention belongs to the technical field of preparation of methylene cyclohexane derivatives in the direction of organic synthesis, and in particular relates to a preparation method of axial chiral methylene cyclohexane derivatives. Background technique [0002] Methylenecyclohexane derivatives, as a class of allene-type compounds with special structure, will produce axial chirality when the olefin terminal contains different substituent groups. In the field of liquid crystal materials, axial chiral methylene cyclohexane derivatives are often used as photomolecular switches, which can regulate the conversion of cholesteric liquid crystals into nematic liquid crystals (R.P.Lemieux and G.B.Schuster, J.Org.Chem., 1993, 58, 100-110.). Since the last century, axial chiral methylene cyclohexane derivatives have been used as the research object of photosensitive liquid crystal materials by many researchers. The structures of axial chiral methylene cyclo...

AI Technical Summary

Problems solved by technology

As an improved method of the Wittig reaction, although the HWE reaction uses more stable olefination reagents such as phosphonamide and phosphonate, it also has the disadvantage of poor atom utilization that cannot be ignored.

[0006] For example, in 1992, Denmark et al. used the addition reaction of chiral phosphonamide and 4-substituted cyclohexanone to obtain the intermediate product of chiral alcohol, which was then eliminated under the action of base to generate axial chiral methylene cyclohexane derivative. Although the ee value of the corresponding product can reach 82%, the reaction is not only complicated but also economical and environmentally friendly (S.Denmark, C.-T.Chen, J.Am.Chem.Soc., 1992, 114 ,10674-10676.)

[0007] Compared with the above two types of methods, there are transition metal-catalyzed reactions, enzyme-catalyzed reactions, and in-situ preparation of chiral Wittig reagents by adding chiral auxiliary agents have been developed and reported, but the examples are relatively rare, and the system is not Mature

Images