Abstract：
To understand the regioselectivity observed in the allylation of pyrimidine nucleosides and to identify the factors directing the reaction, a theoretical study of the regioselective allylation was carried out. Several key points were considered such as: the structure of the deprotonated nucleobase in the presence of Na+; the effect of the solvent on the dissociation and aggregation reactions of thymidine/Na+ ion pair; and the likely allylation reaction mechanisms involved. The results showed that the regioselectivity observed experimentally can be attributed to a greater stability of a dimeric form coupled to an increase of the reaction barrier in THF due to larger Na+ binding to the nucleobase.
摘要：
了解在嘧啶核苷的烯丙基化过程中观察到的区域选择性，并确定指导反应的因素，进行了区域选择性烯丙基化的理论研究。考虑了几个关键点，例如：在Na存在下去质子化的核碱基的结构；溶剂对胸苷/Na离子对的解离和聚集反应的影响；以及可能的烯丙基化反应机理。结果表明，实验观察到的区域选择性可归因于二聚体形式的更高稳定性，该二聚体形式与THF中反应屏障的增加有关，这是由于Na与核碱基的结合更大。
