Division of Chemistry, Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
J Am Chem Soc. 2013 May 22;135(20):7414-7. doi: 10.1021/ja401709k. Epub 2013 May 9.
Herein we disclose an organocatalytic aryl-aryl bond-forming process for the regio- and atroposelective synthesis of 2,2'-diamino-1,1'-binaphthalenes (BINAMs). In the presence of catalytic amounts of axially chiral phosphoric acids, achiral N,N'-binaphthyl hydrazines undergo a facile [3,3]-sigmatropic rearrangement to afford enantiomerically enriched BINAM derivatives in good to excellent yield. This transformation represents the first example of a metal-free, catalytic C(sp(2))-C(sp(2)) bond formation between two aromatic rings with concomitant de novo atroposelective installation of an axis of chirality. Density functional calculations reveal that, in the transition state for C-C bond formation, the phosphoric acid proton of the catalyst is fully transferred to one of the N-atoms of the substrate, and the resulting phosphate acts as a chiral counterion.
在这里，我们披露了一种有机催化的芳基-芳基键形成过程，用于区域和对映选择性合成 2,2'-二氨基-1,1'-联萘（BINAMs）。在轴手性磷酸的催化量存在下，手性 N,N'-联萘肼经历了容易的[3,3]-σ重排，以良好至优异的收率提供对映体富集的 BINAM 衍生物。这种转化代表了首例无金属、催化的 C(sp(2))-C(sp(2))键形成，两个芳环之间存在同时对映选择性安装手性轴。密度泛函计算表明，在 C-C 键形成的过渡态中，催化剂的磷酸质子完全转移到底物的一个 N-原子上，得到的磷酸盐作为手性抗衡离子。
