Claims
- 1. A process for the stereoselective preparation of the Z-configuration in preference to the E-configuration of 1,2-diarylally chloride of the formula I ##STR13## in which R.sup.1 and R.sup.2 represent halogen, and m and n are 1, 2, or 3, which process comprises dehydrating a chlorohydrin of the formula II ##STR14## in which R.sup.1, and R.sup.2, m and n are as defined above, at from -25.degree. to 50.degree. C. in an inert ether or carboxylic acid ester as solvent and in the presence of a carboxylic anhydride or ketene and an organic or inorganic acid.
- 2. The process of claim 1, wherein the solvent used is a cyclic ether or a low-molecular-weight aliphatic carboxylic acid ester.
- 3. The process of claim 1, wherein the dehydration is carried out in the presence of an anhydride of aliphatic monocarboxylic acid.
- 4. The process of claim 1, wherein the process is carried out in the presence of ketene and an organic or inorganic acid.
- 5. The process of claim 1, wherein the process is carried out in the presence of ketene in combination with a catalytic to stoichiometric amount of an organic carboxylic acid, based on the chlorohydrin II.
- 6. The process of claim 1, wherein the dehydration is carried out at from -25.degree. to +30.degree. C.
- 7. The process of claim 1, wherein the process is carried out in the presence of a carboxylic anhydride and an organic or inorganic acid.
- 8. The process of claim 1, wherein the ratio of the Z configuration that is formed to the E configuration is from 8:1 to 15:1.
Priority Claims (2)
Number |
Date |
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3923674 |
Jul 1989 |
DEX |
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3936823 |
Nov 1989 |
DEX |
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Parent Case Info
This application is a continuation of application Ser. No. 07/729,831 now abandoned, filed on Jul. 11, 1991, which is a continuation of Ser. No. 07/547,188, filed Jul. 3, 1990 now abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (2)
Number |
Date |
Country |
1204117 |
May 1986 |
CAX |
2146987 |
May 1985 |
GBX |
Non-Patent Literature Citations (4)
Entry |
Ho et al., "Elimination Reactions in the 1,2-Diphenyl-2-Propyl System", Tetrahedron, vol. 26, pp. 4277-4286, 1970. |
Streitwieser et al., Introduction to Organic Chemistry, pp. 563-564, 1970. |
Morrison and Boyd, Organic Chemistry, pp. 281, 486-487, 318-319, (1983). |
The Merck Index of Chemicals and Drugs, 7th edition pp. 6-7, (1960). |
Continuations (2)
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Parent |
729831 |
Jul 1991 |
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Parent |
547188 |
Jul 1990 |
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