Diastereoselective Alkyl Grignard 1,4-Additions to para-Substituted (2R)-N-Cinnamoylbornane-10,2-sultam Derivatives: Influence of N-Atom Pyramidalization
作者:Anna M. Piątek、Agnieszka Sadowska、Christian Chapuis、Janusz Jurczak
DOI:10.1002/hlca.201100197
日期:2011.12
Several typical 13C‐NMR displacements (of CO, C(α), C(β), and Cipso), as well as conformational or energy properties (SNCO dihedral angle, ΔE syn/anti; HOMO/LUMO) could be correlated with the electronic parameters of p‐substituted N‐cinnamoylbornane‐10,2‐sultams 2. Even under nonchelating conditions, the pyramidalization of the sultam N‐atom decreases for electron‐attracting p‐substituents, inducing
几种典型的13 C-NMR的位移(的CO,C(α),C(β),和C本位),以及构象或能量性质(S Ñ CO二面角,Δ ÈSYN / anti ; HOMO / LUMO)可能与p-取代的N-肉桂酰基冰片烷10,2-sultams 2的电子参数相关。即使在非螯合条件下,对于电子吸引性p取代基,sultam N原子的金字塔化也会减少,从而导致对sultam-ring褶皱的修饰。2b,2d的X射线结构分析的详细比较和2米表明,空间位引导伪轴向SO(2)和H的取向 C(2)被修改,并且排除对任何结论π N个孤对烷基上的-facial立体电子影响格利雅1 ,4-加法。我们还表明,可以以等摩尔方式使用聚集的烷基格氏试剂,这证明了阿s肽被路易斯酸(例如MgBr 2)螯合。所述的Schlenk平衡也可被用来产生有效1,4-非对映选择性的适当的条件。虽然抗-S-顺/ SYN-S-顺对于构象的能量的差ñ