Direct C−H Arylation of Purines: Development of Methodology and Its Use in Regioselective Synthesis of 2,6,8-Trisubstituted Purines
摘要:
[GRAPHICS]Direct C-H arylation of purines to position 8 by diverse aryl iodides was achieved with Pd catalysis in the presence of CuI and Cs2CO3. The methodology is general and efficient and was applied in the consecutive regioselective synthesis of 2,6,8-trisubstituted purines bearing three different C-substituents in combination with two cross-coupling reactions.
The Suzuki-Miyaura Cross-Coupling Reactionsof 2-, 6- or 8-Halopurines with Boronic Acids Leading to 2-, 6- or 8-Aryl- and -Alkenylpurine Derivatives
作者:Martina Havelková、Dalimil Dvořak、Michal Hocek
DOI:10.1055/s-2001-16765
日期:——
The Suzuki-Miyaura cross-coupling reactions of 9-benzyl-6-chloropurine, 9- or 3-benzyl-8-bromoadenine and 2,6-dihalopurines with boronic acids gave the corresponding 6-, 8- or 2-aryl- or -alkenylpurines in good yields. Anhydrous conditions in toluene were superior for coupling of electron-rich boronic acids, while aqueous DME was used for electron-poor arylboronic acids as well as for alkenylboronic acids. A good regioselectivity was observed for the coupling of 2,6-dihalopurines: 9-benzyl-2,6-dichloropurine reacted with one equivalent of phenyl boronic acid to give 9-benzyl-2-chloro-6-phenylpurine, while an analogous reaction of 9-benzyl-6-chloro-2-iodopurine gave selectively 9-benzyl-6-chloro-2-phenylpurine.
Regioselective Pd-mediated coupling between 2,6-dichloropurines and organometallic reagents
作者:Lise-Lotte Gundersen、Geir Langli、Frode Rise
DOI:10.1016/0040-4039(95)00163-7
日期:1995.3
Selective coupling in the purine 6-position has been achieved, by reacting N-benzylated 2,6-dichloropurines with organotin and organozinc reagents. The positional identity products were established from long range HETCOR or nOe NMR experiments.