The Reformatsky-type reaction of 2-bromo-3,3,3-trifluoropropanoic imide with various types of imines, in the presence of ZnBr2 as a Lewis acid in THF at 0 °C for 3 h, gave the corresponding α-trifluoromethyl-β-amino acid derivatives in a highly anti-selective manner.
describe the titanium tetrachloride-mediated reaction of chiral enolates derivedfrom thiazolidine thiones and non-enolizable imines. For example, N-(4-methoxyphenyl)ben- zaldimine (1) yields 2R,3S-(anti)-products with good selectivity, while N-benzyloxycarbonylbenzaldimine (2) equilibrates and sub- sequently eliminates benzyl alkoxide under the reaction conditions to produce 2R,3R-(syn)-isocyanates
不对称曼尼希缩合可以产生对映体纯的氨基羰基官能团,这是许多具有生物活性的天然产物和治疗剂的重要成分。我们描述了由噻唑烷硫酮和非烯醇化亚胺衍生的手性烯醇化物的四氯化钛介导的反应。例如,N-(4-甲氧基苯基)苯甲醛亚胺 (1) 以良好的选择性产生 2R,3S-(反)-产物,而 N-苄氧基羰基苯甲醛亚胺 (2) 在反应条件下平衡并随后消除苄基醇以优异的选择性生产 2R,3R-(syn)-异氰酸酯。通过简单地改变氮上的 Z 基团和反应条件,可以在操作上实现从反到顺的选择性逆转。
PROCESS FOR MANUFACTURING DISULFONIC ACID COMPOUND, ASYMMETRIC MANNICH CATALST, PROCESS FOR MANUFACTURING BETA-AMINOCARBONYL DERIVATIVE, AND NOVEL DISULFONATE
申请人:Ishihara Kazuaki
公开号:US20100249431A1
公开(公告)日:2010-09-30
Hexamethylphosphoramide (HMPA) was added to a reaction vessel containing (R)-1,1′-binaphthyl-2,2′-dithiol and potassium hydroxide. The vessel was purged with oxygen and stirred at 80° C. for 5 days under 7 atmospheres of oxygen. After being cooled to room temperature, the reaction product was purified to yield potassium (R)-1,1′-binaphthyl-2,2′-disulfonate. The (R)-1,1′-binaphthyl-2,2′-disulfonic acid obtained from the disulfonate and 2,6-diphenylpyridine were stirred in acetonitrile, and then the solvent was evaporated under reduced pressure. Subsequently, magnesium sulfate and distilled CH
2
Cl
2
were added to the reaction product, and the mixture was stirred at room temperature for 30 minutes. The resulting solution was cooled to 0° C. Benzaldehyde imine whose nitrogen is protected with Cbz and subsequently acetyl acetone were dropped into the solution over a period of 1 hour. The resulting mixture was further stirred at 0° C. for 30 minutes. A corresponding β-aminocarbonyl derivative was thus produced with an yield of 91% and an enantiomeric excess of 90% ee.