First catalytic enantioselective synthesis of the cocaine abuse therapeutic agent (S)-(+)-1-(4-{2-[bis(4-fluorophenyl)methoxy]ethyl}piperazin-1-yl)-2-phenyl-2-propanol
摘要:
(S)-(+)-1-(4-{2-[Bis(4-fluorophenyl)methoxy]ethyl} piperazin-1-yl)-2-phenyl-2-propanol, which is a promising candidate as a cocaine abuse therapeutic agent, is prepared in several steps. The key asymmetric step is the catalytic enantioselective addition of dimethylzinc to either 2-chloro or 2-bromoacetophenone catalyzed by the use of different chiral isoborneolsulfonamide ligands in the presence of titanium tetraisopropoxide. The synthesis of a new isoborneolsulfonamide ligand bearing a trifluromethyl. substituent and its use in this addition is also presented. (c) 2007 Elsevier Ltd. All rights reserved.
Ruthenium(II) and rhodium(III) catalyzed asymmetric transfer hydrogenation (ATH) of acetophenone in isopropanol and in aqueous sodium formate using new chiral substituted aromatic monosulfonamide ligands derived from (1R,2R)-diaminocyclohexane
摘要:
A series of aromatic monosulfonamide ligands derived from (1R,2R)-diaminocyclohexane were synthesized with electron withdrawing and donating groups. These were complexed with Rh(Cp*) or Ru(arene) and their catalytic efficiencies were compared in the ATH of acetophenone using sodium formate/water or isopropanol/KOH as the hydrogen source. Results suggest that substituents on the benzene ring of the sulfonamide have very little electronic impact on the enantioselectivity and mechanism of the reaction. (C) 2008 Elsevier Ltd. All rights reserved.
Auxiliary‐Free Remote Dearomatizative Nitrenoid Transfer for Enantioselective Construction of Spirolactams
作者:Bo‐Han Zhu、Wen‐Ting Guo、Qing Sun、Peng‐Cheng Qian、Long‐Wu Ye、Long Li
DOI:10.1002/adsc.202101189
日期:2022.1.18
An Ir-catalyzed remotedearomatizative amidation for the enantioselectiveconstruction of chiral spirolactams in 70–93% yield with 81–96% ee was developed. This protocol represented a more atom-economical approach to chiral spirolactams via Ir-catalyzed nitrenoidtransfer without the introduction of a traceless O-silyl achiral auxiliary.
开发了一种 Ir 催化的远程脱芳构酰胺化,用于手性螺内酰胺的对映选择性构建,产率为 70-93%,ee 为 81-96%。该协议代表了一种更原子经济的手性螺内酰胺方法,通过 Ir 催化的 nitrenoid 转移而无需引入无痕 O-甲硅烷基非手性助剂。
Asymmetric addition of diethylzinc to benzaldehyde catalyzed by novel chiral C2-symmetric tetrakis(sulfonamide)–titanium(IV) complexes
A series of chiral C-2-symmetric tetrakis(sulfonamides) 3a-f, 4a-f were prepared and employed as ligands for titanium(IV) complexes in the asymmetric addition of diethylzinc to benzaldehyde. The chiral secondary alcohols were obtained in high yields and in moderate enantioselectivities. (C) 2010 Elsevier Ltd. All rights reserved.