Intramolecular Addition of Triarylmethanes to Alkynes Promoted by KO<i>t</i>Bu/DMF: A Synthetic Approach to Indene Derivatives
作者:Yan-yan Chen、Zhen-yu Chen、Niu-niu Zhang、Jia-hua Chen、Xue-jing Zhang、Ming Yan
DOI:10.1002/ejoc.201501356
日期:2016.1
been developed. The reaction was efficiently promoted by KOtBu/DMF without any transition-metal catalyst. A variety of indene derivatives were prepared in moderate to good yields. A cascade cyclization of 2-alkyl-substituted substrates at elevated reaction temperature gave bicyclic indene derivatives. The reaction is proposed to proceed through the generation of a triphenylmethyl radical.
densely substituted pyridine derivatives from 1-methyl-1,3-(ar)enynes and nitriles via a formal [4+2] cycloaddition has been established. The well-balanced affinities of two alkali metal salts enable C(sp3)–H bond activation and excellent chemo- and regioselectivities. Experimental studies revealed that nitrile functions only as a partial nitrogen source for pyridine synthesis, and the addition of a metalated
Iron(III) Chloride and Diorganyl Diselenide-Promoted Nucleophilic Closures of 1-Benzyl-2-alkynylbenzenes in the Preparation of 9-(Organoselanyl)-5<i>H</i>-benzo[7]annulenes
作者:Thais Prochnow、Davi F. Back、Gilson Zeni
DOI:10.1002/adsc.201501055
日期:2016.3.31
Iron‐promoted cyclization of 1‐benzyl‐2‐alkynylbenzenes with diorganyl diselenides led to the synthesis of 9‐(organoselanyl)‐5H‐benzo[7]annulenes whereby the mutual action between diorganyl diselenides and iron(III) chloride in a 0.5:1.0 mol ratio was essential in order to achieve the maximal yields of the products. The cyclization reaction tolerated a variety of functional groups, such as trifluoromethyl
The C(sp(3))-H functionalization/carbocyclization reaction through the oxidative quenching of visible light photoredox catalysts is established for constructing functionalized 1H-indenes. The process is general for a wide range of benzylic C(sp(3))-H bonds and is highly compatible with common functional groups. Importantly, the visible light photoredox catalysts can be recovered and reused at least three times without loss of catalytic activity.
Flexible and Practical Synthesis of Anthracenes through Gold-Catalyzed Cyclization of<i>o</i>-Alkynyldiarylmethanes
作者:Chao Shu、Cheng-Bin Chen、Wei-Xi Chen、Long-Wu Ye
DOI:10.1021/ol402713g
日期:2013.11
A concise gold-catalyzed method for the preparation of anthracenes from o-alkynyldiarylmethanes has been developed. Under mild reaction conditions, versatile anthracene derivatives were formed in moderate to good yields. The high flexibility, broad substrate scope, and mild nature of this reaction render it a viable alternative for the synthesis of anthracenes.