Cyclization and rearrangement products from coupling reactions between terminal o-alkynylphenols or o-ethynyl(hydroxymethyl)benzene and 6-halopurines

被引：22

作者：

Berg, Tom Christian ^{[1
]}

Bakken, Vebjorn ^{[1
]}

Gundersen, Lise-Lotte ^{[1
]}

Petersen, Dirk ^{[1
]}

机构：

[1] Univ Oslo, Dept Chem, N-0315 Oslo, Norway

来源：

TETRAHEDRON | 2006年 / 62卷 / 25期

关键词：

D O I：

10.1016/j.tet.2006.03.112

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Cyclization reactions on 6-[(2-hydroxyphenyl)ethynyl]purines, 6-[(2-hydroxymethylphenyl)ethynyl]purines and 6-[(2-hydroxyphenyl)propyn- l-yl]purines have been studied. 6-(2-Benzofuryl)purines are readily available via a one-pot Sonogashira coupling-cyclization between 6-iodopurine and 2-ethynylphenol. When the same reaction was performed with o-(hydroxymethyl)ethynylbenzene, 6-[isobenzofuran-1(3H)-ylidenemethyl]purine was formed, mainly as the (E)-isomer. Acid catalyzed isomerization of the (E)-compound afforded the (Z)-isomer. The latter compound was also formed from a two-step reaction; Sonogashira coupling with O-silylated alkyne followed by deprotection and subsequent 5-exo cyclization. Sonogashira coupling between 6-halopurines and 2-propynylphenol gave only the alkyne coupling product and no cyclization took place. However, the Sonogashira product was unexpectedly rearranged to 6-(3-phenoxypropa-1,2-dienyl)purines under basic conditions. Theoretical calculations demonstrated that the allenes are more stable than their alkyne isomers. (c) 2006 Elsevier Ltd. All rights reserved.

引用

页码：6121 / 6131

页数：11

共 54 条

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