Asymmetric synthetic method for chiral epoxy compounds
A technology of epoxy compound and synthesis method, which is applied in the direction of organic chemistry, can solve the problems affecting the application scope, application efficiency and scope, etc., and achieve the effects of good cis-trans selectivity, good reaction yield and mild reaction conditions
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Embodiment 1
[0021] Example 1: This example includes the preparation of chiral tellurium salts and the preparation of chiral epoxy compounds:
[0022] (1) Preparation of chiral tellurium salt: under the protection of nitrogen, a solution of 2.6g of tellurium powder (20mmol) and 2.0g of sodium borohydride (52mmol) in 80ml DMF was stirred at 80°C for 5 hours to obtain light yellow sodium telluride Solution, after cooling the solution to room temperature, add 5.5 g (2S,5S)-2,5-hexane bis-p-methanesulfonate (20 mmol) in 10 ml DMF solution, and stir at 40°C for 12 hours. The resulting mixture was separated by column chromatography to obtain 2.8 g of (2R, 5R)-tetrahydro-2,5-dimethyltelluride with a yield of 65%; 2.1 g of benzyl bromide (12 mmol) was added to 2.1 G (2R,5R)-tetrahydro-2,5-dimethyltellurophene (10mmol) in 10ml anhydrous ether solution, stirred at room temperature for 10 hours, a light yellow precipitate formed; the ether was filtered out, and a light yellow precipitate was used The met...
Embodiment 2
[0024] Example 2: This example includes the preparation of chiral tellurium salts and the preparation of chiral epoxy compounds:
[0025] (1) Preparation of chiral tellurium salt: the same as the preparation of chiral tellurium salt in Example 1;
[0026] (2) Preparation of chiral epoxy compound: slowly drop 1.7 grams of o-chlorobenzaldehyde (12mmol) in acetonitrile (5ml) into 4.6 grams of chiral tellurium salt (12mmol) and 2.0 grams of potassium hydroxide (36mmol). In acetonitrile (20ml) solution, stirred at -10°C for 10 hours. The resulting reaction mixture was filtered to remove solid impurities. The filtrate was concentrated and then subjected to column chromatography to obtain trans-(2S,3S)-1- Phenyl-2-o-chlorophenyl ethylene oxide was 2.0 grams, the yield was 73%, the ratio of cis to trans was 100:0, and the ee value was 86%.
Embodiment 3
[0027] Example 3: This example includes the preparation of chiral tellurium salts and the preparation of chiral epoxy compounds.
[0028] (1) Preparation of chiral tellurium salt: the same as the preparation of chiral tellurium salt in Example 1;
[0029] (2) Preparation of chiral epoxy compound: slowly drop 1.7 grams of o-chlorobenzaldehyde (12mmol) in tetrahydrofuran (5ml) into the above 4.6 grams of chiral tellurium salt (12mmol) and 4.0 grams of potassium tert-butoxide (36mmol). ) In tetrahydrofuran (20ml) and stirred at -10°C for 12 hours. The resulting reaction mixture was filtered to remove solid impurities. The filtrate was concentrated and then subjected to column chromatography to separate the chiral epoxy compound trans-( 2S,3S)-1-phenyl-2-o-chlorophenyl ethylene oxide is 2.2 g, the yield is 80%, the ratio of cis to trans is 100:0, and the ee value is 94%.
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