Concise Synthesis of Chiral N-Benzyl-α,α-Diarylprolinols through Shi Asymmetric Epoxidation
摘要:
A concise and practical synthesis of chiral N-benzyl-alpha,alpha-diaryl-2-prolinols was developed through Shi asymmetric epoxidation, followed by double nucleophilic substitution of bromo-containing olefins. A series of enantioenriched N-benzyl-alpha,alpha-diaryl-2-prolinols were obtained with excellent enantioselectivities (96% ee) in moderate to good yields (40-76% yield). For the first time, enantiopure N-benzyl-alpha,alpha-diphenyl-2-prolinol was obtained from bromo-containing olefin using this methodology.
Compound (1) is useful as a catalyst since compound (III) can be obtained by reacting compound (I) with compound (II) in the presence of compound (I).
In particular, an optically active substance of compound (III) can be produced by using compound (I) which is optically active.
alpha-and beta positions of cyclic amines to their corresponding 3-alkoxyamine lactams is reported. Unlike traditional Cα–H oxidation of amines to amides mediated by transition metals, the present protocol, which involves the use of NaClO2/TEMPO/NaClO in either aqueous or organic solvent, not only allows the Cα–H oxidation but also the subsequent functionalization of the unreactive β-methylene group
据报道,第一种化学方法可以在环胺的α和β位置将其相应的3-烷氧基胺内酰胺选择性地双sp 3 C–H官能化。不同于传统的C α -H胺由过渡金属介导的酰胺的氧化,本协议,该方法涉及使用的NaClO的2 / TEMPO /次氯酸钠在水或有机溶剂,不仅允许Ç α -H氧化也是随后以空前的串联方式并使用环保的反应物将未反应的β-亚甲基官能化。