The first example of benzylic C—H triflylation was accomplished with pyridine as a directing group. The reaction of various 2‐benzylpyridines and (CF3SO2)2O in the presence of NEt3 in CH2Cl2 proceeded smoothly to afford the corresponding benzyl triflones in moderate to high yields.
用吡啶作为指导基团完成苄基CHF3-三氟甲基化的第一个实例。在NEt 3存在下,各种2-苄基吡啶和(CF 3 SO 2)2 O在CH 2 Cl 2中的反应顺利进行,以中等至高收率提供了相应的苄基三氟甲酮。
Transition-Metal Free Chemoselective Hydroxylation and Hydroxylation–Deuteration of Heterobenzylic Methylenes
作者:Yonghai Liu、Yang Yu、Chengyu Sun、Yiwei Fu、Zhiguo Mang、Lei Shi、Hao Li
DOI:10.1021/acs.orglett.0c03108
日期:2020.10.16
We developed an approach for direct selective hydroxylation of heterobenzylic methylenes to secondary alcohols avoiding overoxidation to ketones by using a KOBu-t/DMSO/air system. Most reactions could reach completion in several minutes to give hydroxylated products in 41-76% yields. Using DMSO-d6, this protocol resulted in difunctionalization of heterobenzylic methylenes to afford α-deuterated secondary alcohols (>93% incorporation). By employing this method, active pharmaceutical ingredients carbinoxamine and doxylamine were synthesized in two steps in moderate yields.