Tait Katrina, Horvath Alysia, Blanchard Nicolas, Tam William
Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, Department of Chemistry, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
Laboratoire de Chimie Moléculaire, ECPM-CNRS UMR7509, University of Strasbourg, 25 rue Becquerel, 67087 Strasbourg, France.
Beilstein J Org Chem. 2017 Dec 27;13:2888-2894. doi: 10.3762/bjoc.13.281. eCollection 2017.
The acid-catalyzed ring-opening reactions of a cyclopropanated 3-aza-2-oxabicylic alkene using alcohol nucleophiles were investigated. Although this acid-catalyzed ring-opening reaction did not cleave the cyclopropane unit as planned, this represent the first examples of ring-openings of cyclopropanated 3-aza-2-oxabicyclo[2.2.1]alkenes that lead to the cleavage of the C-O bond instead of the N-O bond. Different acid catalysts were tested and it was found that pyridinium toluenesulfonate in methanol gave the best yields in the ring-opening reactions. The scope of the reaction was successfully expanded to include primary, secondary, and tertiary alcohol nucleophiles. Through X-ray crystallography, the stereochemistry of the product was determined which confirmed an S2-like mechanism to form the ring-opened product.
研究了使用醇亲核试剂对环丙烷化的3-氮杂-2-氧杂双环烯烃进行酸催化开环反应。尽管这种酸催化开环反应并未按计划裂解环丙烷单元，但这代表了环丙烷化的3-氮杂-2-氧杂双环[2.2.1]烯烃开环反应的首个实例，该反应导致C-O键而非N-O键的裂解。测试了不同的酸催化剂，发现甲醇中的对甲苯磺酸吡啶鎓在开环反应中给出了最佳产率。该反应的范围成功扩展到包括伯醇、仲醇和叔醇亲核试剂。通过X射线晶体学确定了产物的立体化学，证实了形成开环产物的类似SN2的机理。
