Periasamy Mariappan, Edukondalu Athukuri, Reddy Polimera Obula
School of Chemistry, University of Hyderabad Central University, Hyderabad 500046, India.
J Org Chem. 2015 Apr 3;80(7):3651-5. doi: 10.1021/jo502688b. Epub 2015 Mar 17.
Racemic 2,3-diaryl-1,4-diazabicyclo[2.2.2]octane (DABCO) derivatives are synthesized from the readily accessible piperazines in 50-64% yield by cyclization using ethylene bromide, triethylamine, and KI at 80 °C. The enantiomerically enriched 2,3-diphenylpiperazine and the 2,3-bis(1-naphthyl)piperazine derivatives are prepared by a resolution method using commercially available optically active acids, yielding the corresponding DABCO derivatives in 51-64% yield with up to 99% ee. This mild cyclization can also be applied to enantiopure camphanyldiamine derivatives, and the products are obtained in 72-86% yields.
外消旋2,3 - 二芳基 - 1,4 - 二氮杂双环[2.2.2]辛烷（DABCO）衍生物由易于获得的哌嗪通过在80°C下使用溴乙烷、三乙胺和碘化钾进行环化反应合成，产率为50 - 64%。对映体富集的2,3 - 二苯基哌嗪和2,3 - 双（1 - 萘基）哌嗪衍生物通过使用市售旋光酸的拆分方法制备，以51 - 64%的产率得到相应的DABCO衍生物，对映体过量率高达99%。这种温和的环化反应也可应用于对映体纯的樟脑二胺衍生物，产物产率为72 - 86%。
