Iron-Catalyzed Dioxygen-Driven C–C Bond Formation: Oxidative Dearomatization of 2-Naphthols with Construction of a Chiral Quaternary Stereocenter
摘要:
Iron(salan) complex 1 was found to catalyze the oxidative dearomatization of 1-substituted 2-naphthols with the formation of an all-carbon quaternary stereocenter in air in the presence of nitroalkanes, to afford the corresponding cyclic enones with high enantioselectivity of 88-96% ee.
Iron-catalysed asymmetric tandem spiro-cyclization using dioxygen in air as the hydrogen acceptor
作者:Takuya Oguma、Tsutomu Katsuki
DOI:10.1039/c4cc01555j
日期:——
A tandem combination of ortho-quinone methide (o-QM) formation/Michael addition/asymmetric dearomatization, which is catalysed by an iron–salan complex in air with high enantioselectivity, provides an efficient method for spirocyclic (2H)-dihydrobenzofuran synthesis from 2-naphthols and phenols.
ortho-Quinone methides are useful transient synthetic intermediates in organic synthesis. These species are most often generated in situ by the acid- or base-mediated transformation of phenols that have been pre-functionalized at a benzylic position, or by biomimetic oxidation of the corresponding ortho-alkylphenols with metal oxidants or transition-metal complexes. Here we describe a method for the
The first visible‐light‐promoted dearomative fluoroalkylation of β‐naphthols was realized without the assistance of any transition‐metal catalysts or external photosensitizers. Inexpensive fluoroalkyl iodides were directly used as efficient fluoroalkylation reagents under very mild reaction conditions. The scope of this process was found to be general and broad, and both trifluoromethyl and perfluoroalkyl
在没有任何过渡金属催化剂或外部光敏剂的帮助下,实现了第一个由可见光促进的β-萘酚脱芳基氟烷基化反应。廉价的氟代烷基碘化物在非常温和的反应条件下直接用作有效的氟代烷基化试剂。发现该方法的范围是一般性的,范围很广,三氟甲基和全氟烷基(-C 4 F 9,-C 6 F 13和-C 8 F 17)以极高的收益进行安装。初步的机理研究表明,在无光催化剂的情况下,萘甲酸酯-氟代烷基碘的电子供体-受体(EDA)复合物中可见光促进了分子间的电荷转移。
Regioselective Oxidative Chlorination of Arenols Using NaCl and Oxone
作者:Muhammet Uyanik、Naoto Sahara、Kazuaki Ishihara
DOI:10.1002/ejoc.201801063
日期:2019.1.10
A practical and efficient chlorination of naphthols and phenols was developed using transient chlorinating species generated in situ from inexpensive sodium chloride and Oxone as a Cl source and oxidant, respectively, under mild conditions.
Chiral Phosphoric Acid Catalyzed Asymmetric Oxidative Dearomatization of Naphthols with Quinones
作者:Gongming Zhu、Guangjun Bao、Yiping Li、Junxian Yang、Wangsheng Sun、Jing Li、Liang Hong、Rui Wang
DOI:10.1021/acs.orglett.6b02609
日期:2016.10.21
A highly enantioselective oxidative dearomatization of naphthols with quinones catalyzed by a chiral spirocyclic phosphoricacid is described. The strategy provides concise access to enantioenriched cyclohexadienones with a quinone moiety. Remarkably, the obtained products could be easily transformed to a potentially useful dihydronaphtho[2,1-b]benzofuran scaffold.
描述了手性螺环磷酸催化的萘醌对苯酚的高度对映选择性氧化脱芳香化反应。该策略为具有醌部分的对映体富集的环己二酮提供了简洁的途径。值得注意的是,所获得的产物可以容易地转化为潜在有用的二氢萘[2,1- b ]苯并呋喃支架。