involving the C9 hydroxyl group, giving novel 6-, 7- and 8-membered rings containing a distorted 1-azabicyclo-[2.2.2]octane framework. TIPS-triflate mediated cyclization of hydroxyaldehydes 13a and 15b to silylated tricyclic hemiacetals 14 and 16 is superior to an intramolecular SN2-approach, especially for the formation of 7- and 8-membered rings.
奎尼丁(1a)乙烯基的适当官能化可实现涉及C9羟基的环化作用,产生含有扭曲的1-氮杂双环-[2.2.2]辛烷骨架的新型6元,7元和8元环。TIPS-三氟甲磺酸酯介导的羟醛13a和15b环化为甲硅烷基化的三环半缩醛14和16优于分子内S N 2-途径,尤其是对于7和8元环的形成。