Catalyst-free cyclization of anthranils and cyclic amines: one-step synthesis of rutaecarpine
作者:Jian Li、Zheng-Bing Wang、Yue Xu、Xue-Chen Lu、Shang-Rong Zhu、Li Liu
DOI:10.1039/c9cc06160f
日期:——
An efficient synthesis of a variety of quinazolinone derivatives via a direct cyclization reaction between commercially available anthranils and cyclic amines is described. The developed transformation proceeds with the merits of high step- and atom-efficiency, a broad substrate scope, and good to excellent yields, without additional catalysts, and offers a practical way for the preparation of rutaecarpine
A visible-light-induced/thiourea-mediated intramolecularcyclization of o-nitroarenes under mild conditions is realized for the first time, which provides an efficient and environmentally friendly way to access pharmaceutical relevant quinazolinone derivatives. The reaction can be easily extended to gram level by using a continuous-flow setup with high efficiency. Mechanistic investigation including
Reported herein is a visible-light-driven intramolecular C-N cross-coupling reaction under mild reaction conditions (metal- and photocatalyst-free, at room temperature) via a long-lived photoactive photoisomer complex. This strategy was used to rapidly prepare the N-substituted polycyclic quinazolinone derivatives with a broad substrate scope (>50 examples) and further exploited to synthesize the natural
A one-pot process for the enantioselective synthesis of tetrahydroquinolines and tetrahydroisoquinolines <i>via</i> asymmetric reductive amination (ARA)
作者:Tao Yang、Qin Yin、Guoxian Gu、Xumu Zhang
DOI:10.1039/c8cc03586e
日期:——
Asymmetric reductiveamination for the synthesis of both chiral tetrahydroquinolines (THQs) and tetrahydroisoquinolines (THIQs) has been realized with an Ir/ZhaoPhos catalytic system via a one-pot N-Boc deprotection/intramolecular asymmetric reductiveamination (ARA) sequence. Control experiments reveal that HCl plays a vital role to the success of this transformation. The HCl acid assists the removal
Ir / ZhaoPhos催化体系通过一锅N - Boc脱保护/分子内不对称还原胺化(ARA)序列实现了用于合成手性四氢喹啉(THQs)和四氢异喹啉(THIQs)的不对称还原胺化。对照实验表明,HCl对这种转化的成功起着至关重要的作用。HCl酸有助于除去N- Boc保护基,还提供氯离子与ZhaoPhos中的硫脲部分相互作用,从而实现出色的反应对映控制。
Activation of Electrophilicity of Stable Y-Delocalized Carbamate Cations in Intramolecular Aromatic Substitution Reaction: Evidence for Formation of Diprotonated Carbamates Leading to Generation of Isocyanates
idea that further protonation of the O-protonated carbamates is involved in the cyclization, but the concentration of the dications is very low and suggests that the rate-determining step is dissociation of methanol from the diprotonated carbamate to generate protonated isocyanate, which reacts with the aromatic ring. Therefore, O-protonated carbamates are weak bases in sharp contrast to other Y-shaped