| 摘要 |
<p>A process for the preparation of compounds of formula (I) wherein R1 is unsubstituted or substituted C1-C8alkyl, R2, R3, R4 and R5 are each independently of the others hydrogen, unsubstituted or substituted C1-C8alkyl, C1-C8 alkoxy, phenoxy or benzyloxy, or halogen, Y1 and Y2 are each independently of the other hydrogen or a protecting group, or Y1 and Y2 together form a protecting bridge, and X1 is hydrogen, an organic radical or a cation, in which process a compound of formula (II) wherein R1 R2, R3, R4 and R5 are as defined above and Z1 is a leaving group, is reacted, in the presence of a catalytically effective amount of a palladium catalyst, with a compound of formula (III) wherein R6 is hydrogen, bromine, chlorine, iodine, -OSO2CF3, -COCI, -B(OH)2 or a mono- or di-ester derived from -B(OH)2, Y3 and Y4 are each a protecting group, or Y3 and Y4 together form a protecting bridge, and X1 is as defined above, to form a compound of formula (IV) and if desired the radicals Y3 and Y4 are converted into the radicals Y1 and Y2 where Y1 and Y2 are hydrogen.</p> |
