15796-70-0Relevant academic research and scientific papers
Efforts directed toward the synthesis of colchicine: Application of palladium-catalyzed siloxane cross-coupling methodology
Seganish, W. Michael,Handy, Christopher J.,DeShong, Philip
, p. 8948 - 8955 (2007/10/03)
Colchicine is an important and synthetically challenging natural product. The key synthetic step in this approach to the synthesis of colchicine involved a palladium-catalyzed cross-coupling reaction between 5-bromotropolone (4) and an aryl siloxane to form the aryl-tropolone bond. The coupling of a variety of highly functionalized aryl siloxane derivatives was investigated and optimized coupling conditions were developed. It was discovered that a palladium catalyst with a high degree of phosphine ligand coordination (5 equiv of phosphine/mol Pd) was necessary to efficiently couple aryl siloxanes with 5-bromotropolone (4). In addition, the coupling approach has provided a direct comparison between siloxane and boronic acid coupling technologies that demonstrated that aryl siloxanes and boronic acids produce similar yields of highly functionalized biaryl products.
Palladium-catalyzed cross-coupling of aryl triethylammonium bis(catechol) silicates with aryl bromides using microwave irradiation
Seganish, W. Michael,DeShong, Philip
, p. 4379 - 4381 (2007/10/03)
(Chemical Equation Presented) The scope of the palladium-catalyzed cross-coupling reaction of aryl bis(catechol) silicates has been extended to include the coupling of aryl bromides by employing microwave irradiation. This new set of coupling conditions is tolerant of electron-rich and -deficient aryl bromides. In addition, a variety of substituted aryl bis(catechol) silicates have been successfully cross-coupled.
Syntheses and ipso-substitution reactions of some C-stannylated troponoids
Banwell, Martin G.,Cameron, Jennifer M.,Collis, Maree P.,Gravatt, G. Lance
, p. 395 - 407 (2007/10/03)
The C-stannylated troponoids (2)-(8) have been prepared and two of these shown to undergo palladium(0)-catalysed cross-coupling with bromobenzene to give the corresponding phenyl-substituted tropone. Compounds (3), (5) and (6)-(8) all react with electrophiles to give products of ipso-substitution.
The Palladium-Mediated Cross Coupling of Bromotropolones with Organostannanes or Arylboronic Acids: Applications to the Synthesis of Natural Products and Natural Product Analogues
Banwell, Martin G.,Cameron, Jennifer M.,Collis, Maree P.,Crisp, Geoffrey T.,Gable, Robert W.,'et al.
, p. 705 - 728 (2007/10/02)
The bromotropolones (4), (5) and (10) undergo palladium-mediated cross coupling with a wide range of organostannanes to produce alkenyl-, alkyl- and aryl-substituted tropolones.The methodology has been applied to the synthesis of the monoterpenes β-dolabrin (11), β-thujaplicin (12), 4-isopropyl-7-methoxytropolone (13) and β-thujaplicinol (14).Cross coupling of bromotropolones (4), (5) and (10) with various aryltrimethylstannanes or arylboronic acids has permitted the preparation of the bicyclic colchicine analogues (30)-(43) which have been tested for tubulin-binding activity.The X-ray crystal structure of the most active of these systems, compound (38), is reported.
A CONVENIENT SYNTHESIS OF 5-ARYLTROPONES
Keenan, Richard M.,Kruse, Lawrence I.
, p. 793 - 798 (2007/10/02)
2-methoxy-5-oxy>tropone was coupled to a variety of arylzinc chlorides in the presence of a palladium catalyst to furnish 5-aryltropones in good to excelent yields.
The Palladium-mediated Cross-coupling of Bromotropolones with Organostannanes; Application to Concise Syntheses of β-Dolabrin, β-Thujaplicin, 7-Methoxy-4-isopropyltropolone, and β-Thujaplicinol
Banwell, Martin G.,Collis, Maree P.,Crisp, Geoffrey T.,Lambert, John N.,Reum, Monica E.,Scoble, Judith A.
, p. 616 - 617 (2007/10/02)
The bromotropolones (1), (2), and (3) cross-couple with organostannanes in the presence of palladium(O) to produce alkyl, alkenyl, or aryl substituted tropolones; the methodology has been applied to the synthesis of the monoterpenes β-dolabrin (4), β-thujaplicin (5), 7-methoxy-4-isopropyltropolone (7), and β-thujaplicinol (8).
