Syntheses of 2-Azafluorenones from 3-Substituted 4-Arylpyridines
作者:Min-Jen Shiao、Kang-Hsiuan Liu、Pen-Yuan Lin
DOI:10.3987/com-92-6199
日期:——
3-Substituted 4-arylpyridines (5a-i) were synthesized in good yields by reaction of mixed copper, zinc aryl organometallics (2a-e) with 1-ethoxycarbonyl-pyridinium chlorides (1a-d) followed by o-chloranil oxidation under reflux in toluene. The 4-arylpyridines (5a-i) are obtained predominantly. Having compounds (5a-i) in hand, a convenient method was developed for the synthesis of 2-azafluorenones (7a-f) by using cyclization of 4-arylpyridines (5a-i) with polyphosphoric acid.
Palladium-Catalyzed Domino Cyclization (5-<i>exo</i>/3-<i>exo</i>), Ring- Expansion by Palladium Rearrangement, and Aromatization: An Expedient Synthesis of 4-Arylnicotinates from Morita-Baylis-Hillman Adducts
作者:Ko Hoon Kim、Se Hee Kim、Hyun Ju Lee、Jae Nyoung Kim
DOI:10.1002/adsc.201300211
日期:2013.7.8
Various 4‐arylnicotinate derivatives were synthesized via a palladium‐catalyzed cascade reaction of N‐(2‐bromoallyl)‐N‐cinnamyltosylamides in a one‐pot procedure in good yields. The reaction involves a domino 5‐exo/3‐exo carbopalladation, ring‐expansion by palladiumrearrangement, and an aromatization process.
Abstract A convenient method for the synthesis of various azafluorenones (2a-f & 4a-d) by cyclization of substituted arylpyridines (1a-f & 3a-d) using zeolites are described.