Chiral bifunctional catalyst 6 promoted anti- and syn-selective cyanosilylation reactions from chiral amino aldehydes derived from phenylalanine in excellent yields. Thus, from dibenzyl protected amino aldehyde 9, syn isomer was obtained as the major product (diastereomeric ratio = 93 : 7) using 3 mol% of 6. On the other hand, from Boc protected aldehyde 10, anti isomer was obtained as the major product (diastereomeric ratio = 97 : 3) by 1 mol% of 6. The experimental results can be rationally explained from the dual activation mechanism of 6. Using syn- and anti-selective cyanosilylation reactions, efficient syntheses of essential chiral building blocks of HIV protease inhibitors and bestatin were achieved.
手性双功能催化剂6促进了来自苯丙
氨酸的手性
氨基醛的反式和顺式选择性
氰硅化反应,产率优异。因此,从二苯基保护的
氨基醛9出发,使用3 mol% 的6获得了顺式异构体作为主要产物(非对映体比 = 93 : 7)。另一方面,从Boc保护的醛10中,通过使用1 mol% 的6获得了反式异构体作为主要产物(非对映体比 = 97 : 3)。实验结果可以通过6的双重活化机制进行合理解释。通过顺式和反式选择性
氰硅化反应,成功合成了HIV蛋白酶抑制剂和贝斯坦的基本手性构建块。