1,3-ジチアン-2-カルボン酸 エチル

使用Ethyl 1,3-dithiane-2-carboxylate is used in syn-selective aldol reactions. It undergoes asymmetric oxidation to give trans bis-sulfoxide. It is used to generate carbanon, which finds application in the preparation of alfa- keto esters.

一般的な説明Ethyl 1,3-dithiane-2-carboxylate is an α-keto acid equivalent and bulky equivalent of acetate. It participates in syn-selective aldol reactions. It can be prepared from the reaction of ethyl diethoxyacetate and 1,3-propanedithiol in the presence of BF3/Et2O. Asymmetric oxidation of ethyl 1,3-dithiane-2-carboxylate by Modena protocol has been reported to afford trans bis-sulfoxide in 60% yield. Carbanion from ethyl 1,3-dithiane-2-carboxylate may be employed for the preparation of α-keto esters.

製造方法To a solution of BF3. Et2O (57.5 mL, 0.454 mmol) in CHC13 (180 mL) heated at reflux was added dropwise, over a 1h period, a solution of 1,3-propanedithiol (22.7 mL, 0.227 mmol), followed by ethyl diethoxyacetate (40 g, 0.227 mmol) in CHCl3 (40 mL). The resulting mixture was heated for 30 minutes, and then cooled to rt. The cooled solution was washed 2 times with water, once with saturated aqueous NaHC03, and then re-washed with water. The combined organic phases were dried over MgS04, then evaporated to give 41 g (94%) of Ethyl 1,3-dithiane-2-carboxylate as a yellow oi. Yield: 94%

純化方法Dissolve the ester in CHCl3, wash with aqueous K2CO3, twice with H2O, dry over MgSO4, filter, evaporate and distil the residue. [Eliel & Hartman J Org Chem 37 505 1972, Seebach Synthesis 1 17 1969, Beilstein 19/7 V 227.]