Functionalization of Piperidine Derivatives for the Site‐Selective and Stereoselective Synthesis of Positional Analogues of Methylphenidate
作者:Wenbin Liu、Tobias Babl、Alexander Röther、Oliver Reiser、Huw M. L. Davies
DOI:10.1002/chem.201905773
日期:2020.4
Rhodium-catalyzed C-H insertions and cyclopropanations of donor/acceptor carbenes have been used for the synthesis of positional analogues of methylphenidate. The site selectivity is controlled by the catalyst and the amine protecting group. C-H functionalization of N-Boc-piperidine using Rh2 (R-TCPTAD)4 , or N-brosyl-piperidine using Rh2 (R-TPPTTL)4 generated 2-substitited analogues. In contrast,
铑催化的供体/受体碳烯的CH插入和环丙烷化已用于合成哌醋甲酯的位置类似物。位置选择性由催化剂和胺保护基控制。使用Rh2(R-TCPTAD)4的N-Boc-哌啶的CH官能化,或使用Rh2(R-TPPTTL)4的N-溴化哌啶的CH官能化生成2取代的类似物。相反,当将N-α-氧代芳基乙酰基-哌啶与Rh2(S-2-Cl-5-BrTPCP)4组合使用时,CH官能化会产生4位被怀疑的类似物。最后,通过N-Boc-四氢吡啶的环丙烷化,然后还原环丙烷的立体和立体选择性开环,间接制备3-取代的类似物。