Development of the Formation of Enolate Controlled by Acid-base Bifunctional Organochalcogenide Catalysts

介绍了手性硫族化合物催化的不对称环丙化、环氧化和氮杂环化反应。以(1S)-10-樟脑磺酸为原料，合成了一种新型的C2对称手性硫醚骨架含异龙脑或樟脑骨架的Lewis酸/Bronsted碱催化剂。二-exo-2-羟基-10-冰片基硒和LiH促进了苯基溴与甲基乙烯基酮的反应，得到了ee高达50%的反式环丙烷。N-亚苄基-4-甲基苯磺酰胺与苯基溴的反应也被硒催化生成60%ee的顺氮杂环丙烷。虽然苯基溴与芳香醛反应生成环氧乙烷的产率较高，对映体选择性适中，但与脂肪醛的反应以较高的产率和较差的对映体选择性得到了所需的环氧化物。

Asymmetric cyclopropanation, epoxidation and aziridination catalyzed by chiral chalcogenides are described. A novel Lewis acid/Bronsted base catalysts formed by a C2 symmetric chiral chalcogenide bearing isoborneol or camphor skeletons were readily prepared from (1S)-10-camphorsulfonic acid. Di-exo-2-hydroxy-10- bornyl selenide and LiH promoted the reaction of phenacyl bromide with methyl vinyl ketone to afford the desired trans cyclopropane with up to 50% ee. The reaction of phenacyl bromide with N-benzylidene-4-methylbenzenesulfonamide was also catalyzed by the selenide to produce the cis aziridine with up to 60% ee. Although the good yields and moderate enantioselectivities for oxirane formations were obtained from the reaction of phenacyl bromide with aromatic aldehydes, the reactions with aliphatic aldehydes afforded the desired epoxides in good yields and poor enantioselectivities.