Enantioselective Synthesis of 1‐Aryl Benzo[5]helicenes Using BINOL‐Derived Cationic Phosphonites as Ancillary Ligands
作者:Pablo Redero、Thierry Hartung、Jianwei Zhang、Leo D. M. Nicholls、Guo Zichen、Martin Simon、Christopher Golz、Manuel Alcarazo
DOI:10.1002/anie.202010021
日期:2020.12.21
The synthesis of unprecedented BINOL‐derived cationic phosphonites is described. Through the use of these phosphanes as ancillary ligands in AuI catalysis, a highly regio‐ and enantioselective assembly of appropriately designed alkynes into 1‐(aryl)benzo[5]carbohelicenes is achieved. The modularsynthesis of these ligands and the enhanced reactivity that they impart to AuI‐centers after coordination
Switchable anthranyl receptors controlled by 1O2 show a different preorganization of the binding sites induced by two combined effects: the structural modification and the on/off mode for the host atropisomerism.
由1 O 2控制的可切换蒽酰基受体显示出由两种组合效应诱导的结合位点的不同预组织:结构修饰和宿主阻转异构现象的开/关模式。
Synthesis and resolution of a new helically chiral azahelicene
作者:Faouzi Aloui、Riadh El Abed、Angéla Marinetti、Béchir Ben Hassine
DOI:10.1016/j.tetlet.2008.04.135
日期:2008.6
Helically chiral azahexahelicene 3 was prepared in four steps using the Mizoroki-Heck coupling followed by classical oxidative photodehydrocyclisation. Resolution of this new chiral system was achieved through separation by HPLC providing (-)- and (+)-3 in high optical purity. The absolute configurations of (-)- and (+)-3 were assigned as M and P, respectively, by means of circular dichroism. Each of the hexa-cyclic systems (M)-(-)- and (P)-(+)-3 was reacted with boron tribromide to provide the corresponding helical pyridophenols in good yields. (C) 2008 Elsevier Ltd. All rights reserved.