The copper-promoted Ullmann reaction of the title diester proceeded with high stereoselectivity to give 24-membered optically pure cyclic dimer of (S,S,S,S)-configuration as well as 12-membered monomeric cycle of (S,S)-configuration. The reaction also gave reduced, open-chain dimer enriched in (S,R,S)-diastereomer over (S,S,S)-counterpart (17% d.e.). Stereochemical course to the cyclic dimer was discussed considering the result that the intermolecular Ullmann coupling of chiral alcohol esters of 1-bromo-2-naphthoic acid poorly induced axial chirality in the joining of the two naphthyl units.
铜促进的乌尔曼反应以高立体选择性生成了 24 元光学纯环二聚体((S,S,S,S)-构型)和 12 元单体循环((S,S,S)-构型)。该反应还产生了还原的开链二聚体,其(S,R,S)-非对映异构体的含量比(S,S,S)-对应物高(17%d.e.)。考虑到 1-bromo-2-naphthoic acid 手性醇酯的分子间乌尔曼偶联在连接两个
萘基单元时很难诱导轴向手性,因此对环状二聚体的立体
化学过程进行了讨论。