Novel and enantioselective syntheses of (R)- and (S)-3-hydroxy-4-(2,4,5-trifluorophenyl)butanoic acid: a synthon for sitagliptin and its derivatives
作者:Meryem Fistikci、Ozlem Gundogdu、Derya Aktas、Hasan Secen、M. Fethi Sahin、Ramazan Altundas、Yunus Kara
DOI:10.1016/j.tet.2012.01.095
日期:2012.3
A new synthetic strategy for (R)- and (S)-3-hydroxy-4-(2,4,5-trifluorophenyl)butanoic acid, a building block in the preparation of sitagliptin and its derivatives, was developed. Pd(OAc)2 catalyzed coupling of 2,4,5-trifluoro-1-iodobenzene with allyl alcohol gave 3-(2,4,5-trifluorophenyl)propanal in a yield of 95%. l-Proline catalyzed reaction of the 3-phenylpropanal (in only 1.2 molar equiv) with
为一个新的合成策略([R )-和(小号)-3-羟基-4-(2,4,5-三氟苯基)丁酸,西他列汀中和它的衍生物的制备建筑物块,被开发。Pd(OAc)2催化2,4,5-三氟-1-碘苯与烯丙醇的偶合,得到3-(2,4,5-三氟苯基)丙醛,产率为95%。1-脯氨酸催化3-苯基丙醛(仅1.2摩尔当量)与亚硝基苯反应,然后用NaBH 4还原,Pd / C催化氢化,得到(R)-3-(2,4,5-三氟苯基)丙烷-1 ,具有> 99%ee和65%收率的1,2-二醇。1,2-丙二醇单元的伯羟基选择性甲苯磺酸化,然后进行氰化物置换(R)-3-羟基-4-(2,4,5-三氟苯基)丁腈(80%)。在碱性水解下,腈以90%的产率转化为标题β-羟基酸。因此,从起始原料通过四个步骤对映选择性地制备了(R)-3-羟基-4-(2,4,5-三氟苯基)丁酸,总产率为45%。用d-脯氨酸作为催化剂重复反应序列,以45%的总收率和>