The present invention has the effect of making it possible to produce 1,1,1-trifluoro-2,2-bisarylethane efficiently by a simple procedure by condensing a mixture of fluoral and hydrogen fluoride with an aryl compound under anhydrous conditions. The purity of the 1,1, 1-trifluoro-2, 2-bisarylethane obtained can be raised by a simple purification method such as crystallization or distillation. The obtained 1,1,1-trifluoro-2,2-bisarylethane can be increased in purity by a simple purification method such as crystallization operation or distillation.

A polyimide which is obtained by a reaction of an aromatic diamine having a 1,1,1-trifluoro-2,2-ethanediyl group (—C(CF.sub.3)H—), as a linkage skeleton, with a tetracarboxylic dianhydride is easily dissolved in an organic solvent and exhibits excellent film forming properties. In addition, the thus-obtained polyimide can be used for an optical film and a display device.

A method for synthesizing 4-hydroxy-3,5-diiodobenzyl alcohol. The synthesis method includes, in just one step, the synthesis of 4-hydroxy-3,5-diiodobenzyl alcohol from 4-hydroxybenzylalcohol, in an aqueous medium at an initial pH of at least 7, containing at least 2 equivalents of diiodide. The method is simple and makes it possible to achieve very good yields at a lower cost.

A method for synthesizing 4-hydroxy-3,5-diiodobenzyl alcohol. The synthesis method includes, in just one step, the synthesis of 4-hydroxy-3,5-diiodobenzyl alcohol from 4-hydroxybenzylalcohol, in an aqueous medium at an initial pH of at least 7, containing at least 2 equivalents of diiodide. The method is simple and makes it possible to achieve very good yields at a lower cost.

A method for synthesizing 4-hydroxy-3,5-diiodobenzyl alcohol. The synthesis method includes, in just one step, the synthesis of 4-hydroxy-3,5-diiodobenzyl alcohol from 4-hydroxybenzylalcohol, in an aqueous medium at an initial pH of at least 7, containing at least 2 equivalents of diiodide. The method is simple and makes it possible to achieve very good yields at a lower cost.

An object of the present invention is to provide a novel method for producing a fluorine-containing methylene compound. The above object can be achieved by a method for producing a compound represented by formula (1):

##STR00001##

wherein R.sup.1 represents an organic group, R.sup.A represents hydrogen or fluorine, R.sup.4a represents hydrogen or an organic group, R.sup.4b represents hydrogen or an organic group, R.sup.5a represents hydrogen or an organic group, R.sup.5b represents hydrogen or an organic group, and R.sup.2 represents hydrogen or an organic group; R.sup.2 is optionally connected to R.sup.4a to form a ring; the method comprising step A of reacting a compound represented by formula (2):

##STR00002##

wherein X.sup.1 represents a leaving group, and other symbols are as defined above, with a compound represented by formula (3):

##STR00003##

wherein X.sup.2 represents a leaving group, and other symbols are as defined above, in the presence of a reducing agent as desired, under light irradiation.

An object of the present invention is to provide a novel method for producing a fluorine-containing methylene compound. The above object can be achieved by a method for producing a compound represented by formula (1):

##STR00001##

wherein R.sup.1 represents an organic group, R.sup.A represents hydrogen or fluorine, R.sup.4a represents hydrogen or an organic group, R.sup.4b represents hydrogen or an organic group, R.sup.5a represents hydrogen or an organic group, R.sup.5b represents hydrogen or an organic group, and R.sup.2 represents hydrogen or an organic group; R.sup.2 is optionally connected to R.sup.4a to form a ring; the method comprising step A of reacting a compound represented by formula (2):

##STR00002##

wherein X.sup.1 represents a leaving group, and other symbols are as defined above, with a compound represented by formula (3):

##STR00003##

wherein X.sup.2 represents a leaving group, and other symbols are as defined above, in the presence of a reducing agent as desired, under light irradiation.

The subject invention pertains to a method of halogenating phenols, yielding a range of halogenated phenols with enantiomeric ratio of up to 99.5:0.5. In certain embodiments, the subject invention pertains to a method of asymmetric halogenation of bisphenol, yielding a range of chiral bisphenol ligands. The novel chiral bisphenols are potent privileged catalyst cores that can be applied to the preparation of ligands for various catalytic asymmetric reactions. The catalyst library can easily be accessed because late-stage modification of the scaffold can readily be executed through cross-coupling of the halogen handles on the bisphenols.

The subject invention pertains to a method of halogenating phenols, yielding a range of halogenated phenols with enantiomeric ratio of up to 99.5:0.5. In certain embodiments, the subject invention pertains to a method of asymmetric halogenation of bisphenol, yielding a range of chiral bisphenol ligands. The novel chiral bisphenols are potent privileged catalyst cores that can be applied to the preparation of ligands for various catalytic asymmetric reactions. The catalyst library can easily be accessed because late-stage modification of the scaffold can readily be executed through cross-coupling of the halogen handles on the bisphenols.

The subject invention pertains to a method of halogenating phenols, yielding a range of halogenated phenols with enantiomeric ratio of up to 99.5:0.5. In certain embodiments, the subject invention pertains to a method of asymmetric halogenation of bisphenol, yielding a range of chiral bisphenol ligands. The novel chiral bisphenols are potent privileged catalyst cores that can be applied to the preparation of ligands for various catalytic asymmetric reactions. The catalyst library can easily be accessed because late-stage modification of the scaffold can readily be executed through cross-coupling of the halogen handles on the bisphenols.