differences in efficiency and product diastereoselectivity. An extremely high number of turnovers (up to 840) was observed. Maximum rate accelerations were measured to be on the order of 105, which numbers among the largest magnitudes of transition state stabilization measured with a synthetic host-catalyst. Host/guest size effects were observed to play an important role in host-mediated enantioselectivity
使用K 12 Ga 4 L 6四面体催化剂评估主体结构对分子内Prins反应的选择性和机理的影响。通过修改螯合部分的结构和芳香族间隔基的大小来改变主体结构。虽然通常观察到
螯合剂取代基的变化会影响速率的变化,但不会影响选择性,但改变主体间隔基会导致效率和产物非对映选择性的差异。观察到失误数量极高(高达 840 次)。测得的最大速率加速度约为 10 5,这是使用合成主体催化剂测得的最大过渡态稳定量级之一。据观察,宿主/客体尺寸效应在宿主介导的对映选择性中发挥重要作用。