Synthesis of chiral 2,2′-dimethyl-1,1′-binaphthyl-8,8′-diamine and barriers of atropisomerization of the related binaphthyls
摘要:
Chiral 2,2'-dimethyl-1,1'-binaphthyl-8,8'-diamine 3b was synthesized via a diastereomeric resolution and determination of the absolute configurations, and the barriers compared for atropisomerization amongst binaphthyl skeletons. (c) 2007 Elsevier Ltd. All rights reserved.
Chiral Atropisomeric 8,8′-Diiodobinaphthalene for Asymmetric Dearomatizing Spirolactonizations in Hypervalent Iodine Oxidations
作者:Toshifumi Dohi、Hirotaka Sasa、Keitaro Miyazaki、Mihoyo Fujitake、Naoko Takenaga、Yasuyuki Kita
DOI:10.1021/acs.joc.7b02037
日期:2017.11.17
A new type of binaphthyl-based chiral iodide functionalized at positions 8 and 8′ of the naphthalene rings has been found as a promising structural motif for the asymmetric hypervalentiodine(III) oxidations, specifically, for the dearomatizing spirocyclization of naphthol carboxylic acids showing expectedly better enantioselectivities versus other atropisomeric biaryls, i.e., a conventionally used
Helical chiral 2-aminopyridinium ions were designed as a significantly more acidic (active) dual hydrogen-bonding catalyst than commonly used (thio)urea-based systems. The heticene framework was specifically utilized to position an inherently chiral barrier on the hydrogen-bonding side of the catalyst. The catalyst reactivity and enantioselectivity were successfully demonstrated in additions of 4,7-dihydroindoles to nitroalkenes (0.5-2 mol % catalyst loadings, up to 98:2 er).