protocol for the construction of 9-(diorganomethylidene)fluorenes through palladium-catalyzed coupling reactions of 2-iodobiphenyls with alkenyl bromides has been reported. The reaction proceeds through the C–H activation/oxidative addition/reduction elimination/intramolecular Heck coupling reaction to afford a series of 9-(diorganomethylidene)fluorenes with good yields. Control experiments demonstrate that
central goal in catalysis. This would be especially interesting when the reactivity and selectivity patterns can be tuned. Herein, we introduced the first Mn-catalyzed selective C-alkylation and olefination of fluorene, and indene with alcohols. Various substrates including benzylic, heteroaromatic, and aliphatic primary and secondary alcohols are employed as alkylating agents. Mechanistic investigations
Synthesis of Benzo[<i>b</i>]fluoranthenes and Spiroacridines from Fluorene-Derived Alkenes and <i>N</i>-Arylimines via a Tandem Reaction with Benzynes
作者:Weihua Wang、Hongwei Wan、Guangfen Du、Bin Dai、Lin He
DOI:10.1021/acs.orglett.9b00659
日期:2019.5.17
Two tandem processes involving the cycloaddition of benzynes have been developed for the synthesis of polyaromatic hydrocarbons. Benzynes react with fluorene-derived alkenes through a tandem Diels–Alder reaction/dehydrogenation process to afford benzo[b]fluoranthenes in 35–87% yields. In addition, an unprecedented [2 + 2] cycloaddition/ring-opening sequence of benzynes and fluorene-derived N-arylimines
已经开发了涉及联苯的环加成的两个串联方法来合成聚芳族烃。通过串联Diels-Alder反应/脱氢过程,苯并zy与芴衍生的烯烃反应,以35-87%的收率得到苯并[ b ]芴。此外,前所未有的[2 + 2]苯并炔和芴衍生的N-芳基嘧啶的环加成/开环顺序可轻松获得螺cr啶,收率为38-79%。
Anionic activation of organic compounds by adsorption on alumina and alumina–KF
作者:Didier Villemin
DOI:10.1039/c39830001092
日期:——
Condensations of acidic carbon compounds with piperonal (1) were achieved by adsorption on neutral alumina without solvent for the more acidic compounds and on Al2O3–KF for the less acidic compounds; dry Michael condensations also took place on Al2O3–KF.
酸性碳化合物与pipe醛(1)的缩合反应是通过在无溶剂的中性氧化铝上吸附较多酸性化合物而在Al 2 O 3 -KF上进行吸附而实现的。干燥的迈克尔缩合反应还发生在Al 2 O 3 -KF上。
ORGANOPHOSPHORUS CHEMISTRY 32. THE REACTION OF VANILLIN, <i>ORTHO</i>-VANILLIN AND PIPERONAL WITH STABILIZED METHYLENETRIPHENYLPHOSPHORANES (WITTIG REAGENTS)
作者:Taghrid S. Hafez、Maged M. Henary、Mohamed Refat、H. Mahran
DOI:10.1080/10426509808045482
日期:1998.12.1
piperonal (3) reacted with ylidenetriphenylphosphoranes 4a-f in boiling toluene following the Wittig mechanism to give the ethylenes 5a-f and 7a-f. Similarly, ethylenes 8c-f were produced when orrho-vanillin (2) was allowed to react with 4c-f. The reaction of aldehyde (2) with the P-ylides 4a,b yielded the Wittig products 8a,b and 8-methoxycoumarin (10). Triphenylphosphine oxide (TPPO, 6) was isolated