753454-92-1Relevant academic research and scientific papers
Iodine-mediated electrophilic cyclization of 2-alkynyl-1-methylene azide aromatics leading to highly substituted isoquinolines and its application to the synthesis of norchelerythrine
Fischer, Dirk,Tomeba, Hisamitsu,Pahadi, Nirmal K.,Patil, Nitin T.,Huo, Zhibao,Yamamoto, Yoshinori
supporting information; scheme or table, p. 15720 - 15725 (2009/03/12)
The reaction of 2-alkynyl-1-methylene azide aromatics 1 with iodine and/or other iodium donors, such as the Barluenga reagent (Py2IBF 4/HBF4) and NIS, gave highly substituted cyclization products, namely, the 1,3-disubstituted 4-iodoisoquinolines 2, in good to high yields. Not only simple 2-alkynyl benzyl azides 1a-j and their substituted analogues 1k-u and 6 but also heteroaromatic analogues, including pyridine 8, pyrroles 10a-c, furane 10d, and thiophenes 10e-g, gave the corresponding isoquinoline derivatives in excellent to allowable yields. Electron-donating and electron-accepting substituents on the aromatic ring were equally tolerated, and either acidic or basic (or even neutral) reaction conditions, depending on the reactivity of the substrate, could be applied to smoothly convert the azide starting materials into the desired isoquinoline products in moderate to good yields. Limits were found only in connection with the substituent at the alkyne terminus, where electron-neutral or electron-donating substituents are clearly favored. The iodine-mediated electrophilic cyclization of 1 most probably proceeds through the iodonium ion intermediate 4 followed by nucleophilic cyclization of the azide and subsequent elimination of N2. This new methodology was successfully applied to the short synthesis of norchelerythrine.
Synthesis of 1,3,4-trisubstituted isoquinolines by iodine-mediated electrophilic cyclization of 2-alkynyl benzyl azides
Fischer, Dirk,Tomeba, Hisamitsu,Pahadi, Nirmal K.,Patil, Nitin T.,Yamamoto, Yoshinori
, p. 4764 - 4766 (2008/02/10)
(Chemical Equation Presented) The I's have it: A series of 2-alkynyl benzyl azides have been smoothly converted into 1,3,4-trisubstituted isoquinolines in moderate to excellent yields by an iodonium-mediated synthesis (see scheme). Depending on the struct
Palladium-catalyzed esterification-hydroarylation reactions of 2-alkynyl-benzaldehydes with aryl iodides in methanol
Wei, Li-Lan,Wei, Li-Mei,Pan, Wen-Bin,Wu, Ming-Jung
, p. 1497 - 1502 (2007/10/03)
The reaction of 2-alkynylbenzaldehydes with aryl iodides in the presence of Pd(PPh3)4 and K2CO3 in refluxing methanol for 24 hours gave the dehydrogenation-addition products, methyl 2-(2,2-disubstituted-vinyl)benzoates in modest yields; together with the cyclization products, 3-methoxy-1-monosubstituted-methylene-3- hydroisobenzofurans in 3-18% yields.
