Journal article
THE PALLADIUM-MEDIATED CROSS COUPLING OF BROMOTROPOLONES WITH ORGANOSTANNANES OR ARYLBORONIC ACIDS - APPLICATIONS TO THE SYNTHESIS OF NATURAL-PRODUCTS AND NATURAL PRODUCT ANALOGS
MG BANWELL, JM CAMERON, MP COLLIS, GT CRISP, RW GABLE, E HAMEL, JN LAMBERT, MF MACKAY, ME REUM, JA SCOBLE
AUSTRALIAN JOURNAL OF CHEMISTRY | C S I R O PUBLICATIONS | Published : 1991
DOI: 10.1071/CH9910705
Abstract
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 ß- dolabrin (11),ß- thujaplicin (12), 4-isopropyl-7-methoxytropolone (13) and ß- 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.